Format call arguments as a string.

        This is used to make test failure messages more helpful by referring
        to calls using a string that matches how they were, or should have been
        called.

        >>> call = Call('arg1', 'arg2', kwarg='kwarg')
        >>> call.formatted_args
        "('arg1', 'arg2', kwarg='kwarg')"

def formatted_args(self):
        """Format call arguments as a string.

        This is used to make test failure messages more helpful by referring
        to calls using a string that matches how they were, or should have been
        called.

        >>> call = Call('arg1', 'arg2', kwarg='kwarg')
        >>> call.formatted_args
        "('arg1', 'arg2', kwarg='kwarg')"

        """
        arg_reprs = list(map(repr, self.args))
        kwarg_reprs = ['%s=%s' % (k, repr(v)) for k, v in self.kwargs.items()]
        return '(%s)' % ', '.join(arg_reprs + kwarg_reprs)