core(ComplexityVisitor): don't count lambdas in cyclomatic complexity

As part of #68

radon/tests/test_complexity_visitor.py

@@ -137,8 +137,13 @@
      finally: pass
      ''', 3),
 
+    # Lambda are not counted anymore as per #68
     ('''
      k = lambda a, b: k(b, a)
+     ''', 1),
+
+    ('''
+     k = lambda a, b, c: c if a else b
      ''', 2),
 
     ('''

radon/visitors.py

@@ -204,8 +204,9 @@ def generic_visit(self, node):
             self.complexity += len(node.handlers) + len(node.orelse)
         elif name == 'BoolOp':
             self.complexity += len(node.values) - 1
-        # Lambda functions, ifs, with and assert statements count all as 1.
-        elif name in ('Lambda', 'With', 'If', 'IfExp'):
+        # Ifs, with and assert statements count all as 1.
+        # Note: Lambda functions are not counted anymore, see #68
+        elif name in ('With', 'If', 'IfExp'):
             self.complexity += 1
         # The For and While blocks count as 1 plus the `else` block.
         elif name in ('For', 'While'):
@@ -237,7 +238,7 @@ def visit_FunctionDef(self, node):
             visitor = ComplexityVisitor(off=False, no_assert=self.no_assert)
             visitor.visit(child)
             clojures.extend(visitor.functions)
-            # Add general complexity and clojures' complexity
+            # Add general complexity but not clojures' complexity, see #68
             body_complexity += visitor.complexity
 
         func = Function(node.name, node.lineno, node.col_offset,