Disallow .__call__() as workaround for non-named functions

Author: alexmojaki

pandas/core/computation/expr.py

@@ -640,7 +640,7 @@ def visit_Attribute(self, node, **kwargs):
 
     def visit_Call(self, node, side=None, **kwargs):
 
-        if isinstance(node.func, ast.Attribute):
+        if isinstance(node.func, ast.Attribute) and node.func.attr != "__call__":
             res = self.visit_Attribute(node.func)
         elif not isinstance(node.func, ast.Name):
             raise TypeError("Only named functions are supported")