BUG: Fix bug when using eval to call "str" methods

Author: dtpc

pandas/core/computation/expr.py

@@ -632,11 +632,8 @@ def visit_Call_35(self, node, side=None, **kwargs):
                 if not isinstance(key, ast.keyword):
                     raise ValueError("keyword error in function call "
                                      "'{func}'".format(func=node.func.id))
-
                 if key.arg:
-                    # TODO: bug?
-                    kwargs.append(ast.keyword(
-                        keyword.arg, self.visit(keyword.value)))  # noqa
+                    kwargs[key.arg] = self.visit(key.value)()
 
             return self.const_type(res(*new_args, **kwargs), self.env)