diff --git a/docs/providers/configuration.rst b/docs/providers/configuration.rst
index 0ce046e6..496cb69d 100644
--- a/docs/providers/configuration.rst
+++ b/docs/providers/configuration.rst
@@ -16,8 +16,8 @@ Configuration provider
 
 .. literalinclude:: ../../examples/providers/configuration/configuration.py
    :language: python
-   :emphasize-lines: 4,9-10
-   :lines: 4-14
+   :emphasize-lines: 7,12-13
+   :lines: 3-
 
 It implements the principle "use first, define later".
 
@@ -29,8 +29,8 @@ Loading from an INI file
 
 .. literalinclude:: ../../examples/providers/configuration/configuration_ini.py
    :language: python
-   :lines: 3-5,6-
-   :emphasize-lines: 6
+   :lines: 3-
+   :emphasize-lines: 12
 
 where ``examples/providers/configuration/config.ini`` is:
 
@@ -49,8 +49,8 @@ Loading from a YAML file
 
 .. literalinclude:: ../../examples/providers/configuration/configuration_yaml.py
    :language: python
-   :lines: 3-5,6-
-   :emphasize-lines: 6
+   :lines: 3-
+   :emphasize-lines: 12
 
 where ``examples/providers/configuration/config.yml`` is:
 
@@ -83,8 +83,8 @@ Loading from a dictionary
 
 .. literalinclude:: ../../examples/providers/configuration/configuration_dict.py
    :language: python
-   :lines: 3-5,6-
-   :emphasize-lines: 6-13
+   :lines: 3-
+   :emphasize-lines: 12-19
 
 Loading from an environment variable
 ------------------------------------
@@ -94,8 +94,8 @@ Loading from an environment variable
 
 .. literalinclude:: ../../examples/providers/configuration/configuration_env.py
    :language: python
-   :lines: 5-7,13-21
-   :emphasize-lines: 6-8
+   :lines: 3-
+   :emphasize-lines: 18-20
 
 Loading from the multiple sources
 ---------------------------------
@@ -105,8 +105,8 @@ configuration is merged recursively over the existing configuration.
 
 .. literalinclude:: ../../examples/providers/configuration/configuration_multiple.py
    :language: python
-   :lines: 3-5,6-14
-   :emphasize-lines: 6-7
+   :lines: 3-
+   :emphasize-lines: 12-13
 
 where ``examples/providers/configuration/config.local.yml`` is:
 
@@ -124,7 +124,7 @@ convert it into an ``int`` or a ``float``.
 .. literalinclude:: ../../examples/providers/configuration/configuration_type.py
    :language: python
    :lines: 3-
-   :emphasize-lines: 17
+   :emphasize-lines: 19
 
 ``Configuration`` provider has next helper methods:
 
@@ -137,10 +137,27 @@ The last method ``.as_(callback, *args, **kwargs)`` helps to implement other con
 .. literalinclude:: ../../examples/providers/configuration/configuration_type_custom.py
    :language: python
    :lines: 3-
-   :emphasize-lines: 16
+   :emphasize-lines: 18
 
 With the ``.as_(callback, *args, **kwargs)`` you can specify a function that will be called
 before the injection. The value from the config will be passed as a first argument. The returned
 value will be injected. Parameters ``*args`` and ``**kwargs`` are handled as any other injections.
 
+Injecting invariants
+--------------------
+
+You can inject invariant configuration options based on the value of the other configuration
+option.
+
+To use that you should provide the switch-value as an item of the configuration option that
+contains sections ``config.options[config.switch]``:
+
+- When the value of the ``config.switch`` is ``A``, the ``config.options.A`` is injected
+- When the value of the ``config.switch`` is ``B``, the ``config.options.B`` is injected
+
+.. literalinclude:: ../../examples/providers/configuration/configuration_itemselector.py
+   :language: python
+   :lines: 3-
+   :emphasize-lines: 15,30-31,38
+
 .. disqus::
diff --git a/examples/providers/configuration/configuration.py b/examples/providers/configuration/configuration.py
index a1ea0f44..7a11cbfc 100644
--- a/examples/providers/configuration/configuration.py
+++ b/examples/providers/configuration/configuration.py
@@ -1,21 +1,24 @@
 """`Configuration` provider example."""
 
 import boto3
-from dependency_injector import providers
+from dependency_injector import containers, providers
 
 
-config = providers.Configuration()
+class Container(containers.DeclarativeContainer):
 
-s3_client_factory = providers.Factory(
-    boto3.client,
-    's3',
-    aws_access_key_id=config.aws.access_key_id,
-    aws_secret_access_key=config.aws.secret_access_key,
-)
+    config = providers.Configuration()
+
+    s3_client_factory = providers.Factory(
+        boto3.client,
+        's3',
+        aws_access_key_id=config.aws.access_key_id,
+        aws_secret_access_key=config.aws.secret_access_key,
+    )
 
 
 if __name__ == '__main__':
-    config.from_dict(
+    container = Container()
+    container.config.from_dict(
         {
             'aws': {
                  'access_key_id': 'KEY',
@@ -23,4 +26,4 @@ if __name__ == '__main__':
              },
         },
     )
-    s3_client = s3_client_factory()
+    s3_client = container.s3_client_factory()
diff --git a/examples/providers/configuration/configuration_dict.py b/examples/providers/configuration/configuration_dict.py
index 275c2b12..d5669ccc 100644
--- a/examples/providers/configuration/configuration_dict.py
+++ b/examples/providers/configuration/configuration_dict.py
@@ -1,20 +1,34 @@
 """`Configuration` provider values loading example."""
 
-from dependency_injector import providers
+from dependency_injector import containers, providers
 
 
-config = providers.Configuration()
+class Container(containers.DeclarativeContainer):
 
-config.from_dict(
-    {
+    config = providers.Configuration()
+
+
+if __name__ == '__main__':
+    container = Container()
+
+    container.config.from_dict(
+        {
+            'aws': {
+                 'access_key_id': 'KEY',
+                 'secret_access_key': 'SECRET',
+             },
+        },
+    )
+
+    assert container.config() == {
         'aws': {
-             'access_key_id': 'KEY',
-             'secret_access_key': 'SECRET',
-         },
-    },
-)
-
-assert config() == {'aws': {'access_key_id': 'KEY', 'secret_access_key': 'SECRET'}}
-assert config.aws() == {'access_key_id': 'KEY', 'secret_access_key': 'SECRET'}
-assert config.aws.access_key_id() == 'KEY'
-assert config.aws.secret_access_key() == 'SECRET'
+            'access_key_id': 'KEY',
+            'secret_access_key': 'SECRET',
+        },
+    }
+    assert container.config.aws() == {
+        'access_key_id': 'KEY',
+        'secret_access_key': 'SECRET',
+    }
+    assert container.config.aws.access_key_id() == 'KEY'
+    assert container.config.aws.secret_access_key() == 'SECRET'
diff --git a/examples/providers/configuration/configuration_env.py b/examples/providers/configuration/configuration_env.py
index 52c3e0ca..b9d491bc 100644
--- a/examples/providers/configuration/configuration_env.py
+++ b/examples/providers/configuration/configuration_env.py
@@ -2,20 +2,25 @@
 
 import os
 
-from dependency_injector import providers
+from dependency_injector import containers, providers
 
 
-# Emulate environment variables
-os.environ['AWS_ACCESS_KEY_ID'] = 'KEY'
-os.environ['AWS_SECRET_ACCESS_KEY'] = 'SECRET'
+class Container(containers.DeclarativeContainer):
+
+    config = providers.Configuration()
 
 
-config = providers.Configuration()
+if __name__ == '__main__':
+    container = Container()
 
-config.aws.access_key_id.from_env('AWS_ACCESS_KEY_ID')
-config.aws.secret_access_key.from_env('AWS_SECRET_ACCESS_KEY')
-config.optional.from_env('UNDEFINED', 'default_value')
+    # Emulate environment variables
+    os.environ['AWS_ACCESS_KEY_ID'] = 'KEY'
+    os.environ['AWS_SECRET_ACCESS_KEY'] = 'SECRET'
 
-assert config.aws.access_key_id() == 'KEY'
-assert config.aws.secret_access_key() == 'SECRET'
-assert config.optional() == 'default_value'
+    container.config.aws.access_key_id.from_env('AWS_ACCESS_KEY_ID')
+    container.config.aws.secret_access_key.from_env('AWS_SECRET_ACCESS_KEY')
+    container.config.optional.from_env('UNDEFINED', 'default_value')
+
+    assert container.config.aws.access_key_id() == 'KEY'
+    assert container.config.aws.secret_access_key() == 'SECRET'
+    assert container.config.optional() == 'default_value'
diff --git a/examples/providers/configuration/configuration_ini.py b/examples/providers/configuration/configuration_ini.py
index 0533a8ae..98783bd0 100644
--- a/examples/providers/configuration/configuration_ini.py
+++ b/examples/providers/configuration/configuration_ini.py
@@ -1,13 +1,27 @@
 """`Configuration` provider values loading example."""
 
-from dependency_injector import providers
+from dependency_injector import containers, providers
 
 
-config = providers.Configuration()
+class Container(containers.DeclarativeContainer):
 
-config.from_ini('examples/providers/configuration/config.ini')
+    config = providers.Configuration()
 
-assert config() == {'aws': {'access_key_id': 'KEY', 'secret_access_key': 'SECRET'}}
-assert config.aws() == {'access_key_id': 'KEY', 'secret_access_key': 'SECRET'}
-assert config.aws.access_key_id() == 'KEY'
-assert config.aws.secret_access_key() == 'SECRET'
+
+if __name__ == '__main__':
+    container = Container()
+
+    container.config.from_ini('examples/providers/configuration/config.ini')
+
+    assert container.config() == {
+        'aws': {
+            'access_key_id': 'KEY',
+            'secret_access_key': 'SECRET',
+        },
+    }
+    assert container.config.aws() == {
+        'access_key_id': 'KEY',
+        'secret_access_key': 'SECRET',
+    }
+    assert container.config.aws.access_key_id() == 'KEY'
+    assert container.config.aws.secret_access_key() == 'SECRET'
diff --git a/examples/providers/configuration/configuration_itemselector.py b/examples/providers/configuration/configuration_itemselector.py
index fd60a616..eb257843 100644
--- a/examples/providers/configuration/configuration_itemselector.py
+++ b/examples/providers/configuration/configuration_itemselector.py
@@ -1,11 +1,8 @@
-"""`Configuration` provider dynamic item selector.
-
-Details: https://github.com/ets-labs/python-dependency-injector/issues/274
-"""
+"""`Configuration` provider dynamic item selector."""
 
 import dataclasses
 
-from dependency_injector import providers
+from dependency_injector import containers, providers
 
 
 @dataclasses.dataclass
@@ -14,34 +11,37 @@ class Foo:
     option2: object
 
 
-config = providers.Configuration(default={
-    'target': 'A',
-    'items': {
-        'A': {
-            'option1': 60,
-            'option2': 80,
-        },
-        'B': {
-            'option1': 10,
-            'option2': 20,
-        },
-    },
-})
+class Container(containers.DeclarativeContainer):
 
-foo = providers.Factory(
-    Foo,
-    option1=config.items[config.target].option1,
-    option2=config.items[config.target].option2,
-)
+    config = providers.Configuration(default={
+        'target': 'A',
+        'items': {
+            'A': {
+                'option1': 60,
+                'option2': 80,
+            },
+            'B': {
+                'option1': 10,
+                'option2': 20,
+            },
+        },
+    })
+
+    foo_factory = providers.Factory(
+        Foo,
+        option1=config.items[config.target].option1,
+        option2=config.items[config.target].option2,
+    )
 
 
 if __name__ == '__main__':
-    config.target.from_env('TARGET')
-    f = foo()
-    print(f.option1, f.option2)
+    container = Container()
 
+    container.config.target.from_env('TARGET')
+    foo = container.foo_factory()
+    print(foo.option1, foo.option2)
 
-# $ TARGET=A python configuration_itemselector.py
-# 60 80
-# $ TARGET=B python configuration_itemselector.py
-# 10 20
+    # $ TARGET=A python configuration_itemselector.py
+    # 60 80
+    # $ TARGET=B python configuration_itemselector.py
+    # 10 20
diff --git a/examples/providers/configuration/configuration_multiple.py b/examples/providers/configuration/configuration_multiple.py
index 4b85c87b..ac95b3e2 100644
--- a/examples/providers/configuration/configuration_multiple.py
+++ b/examples/providers/configuration/configuration_multiple.py
@@ -1,14 +1,28 @@
 """`Configuration` provider values loading example."""
 
-from dependency_injector import providers
+from dependency_injector import containers, providers
 
 
-config = providers.Configuration()
+class Container(containers.DeclarativeContainer):
 
-config.from_yaml('examples/providers/configuration/config.yml')
-config.from_yaml('examples/providers/configuration/config.local.yml')
+    config = providers.Configuration()
 
-assert config() == {'aws': {'access_key_id': 'LOCAL-KEY', 'secret_access_key': 'LOCAL-SECRET'}}
-assert config.aws() == {'access_key_id': 'LOCAL-KEY', 'secret_access_key': 'LOCAL-SECRET'}
-assert config.aws.access_key_id() == 'LOCAL-KEY'
-assert config.aws.secret_access_key() == 'LOCAL-SECRET'
+
+if __name__ == '__main__':
+    container = Container()
+
+    container.config.from_yaml('examples/providers/configuration/config.yml')
+    container.config.from_yaml('examples/providers/configuration/config.local.yml')
+
+    assert container.config() == {
+        'aws': {
+            'access_key_id': 'LOCAL-KEY',
+            'secret_access_key': 'LOCAL-SECRET',
+        },
+    }
+    assert container.config.aws() == {
+        'access_key_id': 'LOCAL-KEY',
+        'secret_access_key': 'LOCAL-SECRET',
+    }
+    assert container.config.aws.access_key_id() == 'LOCAL-KEY'
+    assert container.config.aws.secret_access_key() == 'LOCAL-SECRET'
diff --git a/examples/providers/configuration/configuration_type.py b/examples/providers/configuration/configuration_type.py
index 213f9f79..8c8e044d 100644
--- a/examples/providers/configuration/configuration_type.py
+++ b/examples/providers/configuration/configuration_type.py
@@ -2,7 +2,7 @@
 
 import os
 
-from dependency_injector import providers
+from dependency_injector import containers, providers
 
 
 class ApiClient:
@@ -11,24 +11,28 @@ class ApiClient:
         self.timeout = timeout
 
 
-config = providers.Configuration()
+class Container(containers.DeclarativeContainer):
 
-api_client_factory = providers.Factory(
-    ApiClient,
-    api_key=config.api.key,
-    timeout=config.api.timeout.as_int(),
-)
+    config = providers.Configuration()
+
+    api_client_factory = providers.Factory(
+        ApiClient,
+        api_key=config.api.key,
+        timeout=config.api.timeout.as_int(),
+    )
 
 
 if __name__ == '__main__':
+    container = Container()
+
     # Emulate environment variables
     os.environ['API_KEY'] = 'secret'
     os.environ['API_TIMEOUT'] = '5'
 
-    config.api.key.from_env('API_KEY')
-    config.api.timeout.from_env('API_TIMEOUT')
+    container.config.api.key.from_env('API_KEY')
+    container.config.api.timeout.from_env('API_TIMEOUT')
 
-    api_client = api_client_factory()
+    api_client = container.api_client_factory()
 
     assert api_client.api_key == 'secret'
     assert api_client.timeout == 5
diff --git a/examples/providers/configuration/configuration_type_custom.py b/examples/providers/configuration/configuration_type_custom.py
index 9b53dafe..6782ab52 100644
--- a/examples/providers/configuration/configuration_type_custom.py
+++ b/examples/providers/configuration/configuration_type_custom.py
@@ -3,7 +3,7 @@
 import os
 import decimal
 
-from dependency_injector import providers
+from dependency_injector import containers, providers
 
 
 class Calculator:
@@ -11,20 +11,24 @@ class Calculator:
         self.pi = pi
 
 
-config = providers.Configuration()
+class Container(containers.DeclarativeContainer):
 
-calculator_factory = providers.Factory(
-    Calculator,
-    pi=config.pi.as_(decimal.Decimal),
-)
+    config = providers.Configuration()
+
+    calculator_factory = providers.Factory(
+        Calculator,
+        pi=config.pi.as_(decimal.Decimal),
+    )
 
 
 if __name__ == '__main__':
+    container = Container()
+
     # Emulate environment variables
     os.environ['PI'] = '3.1415926535897932384626433832'
 
-    config.pi.from_env('PI')
+    container.config.pi.from_env('PI')
 
-    calculator = calculator_factory()
+    calculator = container.calculator_factory()
 
     assert calculator.pi == decimal.Decimal('3.1415926535897932384626433832')
diff --git a/examples/providers/configuration/configuration_yaml.py b/examples/providers/configuration/configuration_yaml.py
index 842b4ae8..d281aaf0 100644
--- a/examples/providers/configuration/configuration_yaml.py
+++ b/examples/providers/configuration/configuration_yaml.py
@@ -1,13 +1,27 @@
 """`Configuration` provider values loading example."""
 
-from dependency_injector import providers
+from dependency_injector import containers, providers
 
 
-config = providers.Configuration()
+class Container(containers.DeclarativeContainer):
 
-config.from_yaml('examples/providers/configuration/config.yml')
+    config = providers.Configuration()
 
-assert config() == {'aws': {'access_key_id': 'KEY', 'secret_access_key': 'SECRET'}}
-assert config.aws() == {'access_key_id': 'KEY', 'secret_access_key': 'SECRET'}
-assert config.aws.access_key_id() == 'KEY'
-assert config.aws.secret_access_key() == 'SECRET'
+
+if __name__ == '__main__':
+    container = Container()
+
+    container.config.from_yaml('examples/providers/configuration/config.yml')
+
+    assert container.config() == {
+        'aws': {
+            'access_key_id': 'KEY',
+            'secret_access_key': 'SECRET',
+        },
+    }
+    assert container.config.aws() == {
+        'access_key_id': 'KEY',
+        'secret_access_key': 'SECRET',
+    }
+    assert container.config.aws.access_key_id() == 'KEY'
+    assert container.config.aws.secret_access_key() == 'SECRET'