diff --git a/spacy/matcher/matcher.pyx b/spacy/matcher/matcher.pyx
index 3d99f117a..4cfab915f 100644
--- a/spacy/matcher/matcher.pyx
+++ b/spacy/matcher/matcher.pyx
@@ -213,28 +213,28 @@ cdef class Matcher:
                 else:
                     yield doc
 
-    def __call__(self, object obj):
+    def __call__(self, object doc_or_span):
         """Find all token sequences matching the supplied pattern.
 
-        obj (Doc / Span): The document to match over.
+        doc_or_span (Doc or Span): The document to match over.
         RETURNS (list): A list of `(key, start, end)` tuples,
             describing the matches. A match tuple describes a span
             `doc[start:end]`. The `label_id` and `key` are both integers.
         """
-        if isinstance(obj, Doc):
-            doc = obj
+        if isinstance(doc_or_span, Doc):
+            doc = doc_or_span
             length = len(doc)
-        elif isinstance(obj, Span):
-            doc = obj.doc
-            length = obj.end - obj.start
+        elif isinstance(doc_or_span, Span):
+            doc = doc_or_span.doc
+            length = doc_or_span.end - doc_or_span.start
         else:
-            raise ValueError(Errors.E195.format(good="Doc or Span", got=type(obj).__name__))
+            raise ValueError(Errors.E195.format(good="Doc or Span", got=type(doc_or_span).__name__))
         if len(set([LEMMA, POS, TAG]) & self._seen_attrs) > 0 \
           and not doc.is_tagged:
             raise ValueError(Errors.E155.format())
         if DEP in self._seen_attrs and not doc.is_parsed:
             raise ValueError(Errors.E156.format())
-        matches = find_matches(&self.patterns[0], self.patterns.size(), obj, length,
+        matches = find_matches(&self.patterns[0], self.patterns.size(), doc_or_span, length, 
                                 extensions=self._extensions, predicates=self._extra_predicates)
         for i, (key, start, end) in enumerate(matches):
             on_match = self._callbacks.get(key, None)
@@ -257,7 +257,7 @@ def unpickle_matcher(vocab, patterns, callbacks):
     return matcher
 
 
-cdef find_matches(TokenPatternC** patterns, int n, object obj, int length, extensions=None, predicates=tuple()):
+cdef find_matches(TokenPatternC** patterns, int n, object doc_or_span, int length, extensions=None, predicates=tuple()):
     """Find matches in a doc, with a compiled array of patterns. Matches are
     returned as a list of (id, start, end) tuples.
 
@@ -286,7 +286,7 @@ cdef find_matches(TokenPatternC** patterns, int n, object obj, int length, exten
     else:
         nr_extra_attr = 0
         extra_attr_values = <attr_t*>mem.alloc(length, sizeof(attr_t))
-    for i, token in enumerate(obj):
+    for i, token in enumerate(doc_or_span):
         for name, index in extensions.items():
             value = token._.get(name)
             if isinstance(value, basestring):
@@ -298,7 +298,7 @@ cdef find_matches(TokenPatternC** patterns, int n, object obj, int length, exten
         for j in range(n):
             states.push_back(PatternStateC(patterns[j], i, 0))
         transition_states(states, matches, predicate_cache,
-            obj[i], extra_attr_values, predicates)
+            doc_or_span[i], extra_attr_values, predicates)
         extra_attr_values += nr_extra_attr
         predicate_cache += len(predicates)
     # Handle matches that end in 0-width patterns