How to use the lime.utils.generic_utils.has_arg function in lime

def filter_params(self, fn, override=None):
        """Filters `target_params` and return those in `fn`'s arguments.
        Args:
            fn : arbitrary function
            override: dict, values to override target_params
        Returns:
            result : dict, dictionary containing variables
            in both target_params and fn's arguments.
        """
        override = override or {}
        result = {}
        for name, value in self.target_params.items():
            if has_arg(fn, name):
                result.update({name: value})
        result.update(override)
        return result

if self.target_fn is None:
            if callable(self):
                a_valid_fn.append(self.__call__)
            else:
                raise TypeError('invalid argument: tested object is not callable,\
                 please provide a valid target_fn')
        elif isinstance(self.target_fn, types.FunctionType) \
                or isinstance(self.target_fn, types.MethodType):
            a_valid_fn.append(self.target_fn)
        else:
            a_valid_fn.append(self.target_fn.__call__)

        if not isinstance(parameters, str):
            for p in parameters:
                for fn in a_valid_fn:
                    if has_arg(fn, p):
                        pass
                    else:
                        raise ValueError('{} is not a valid parameter'.format(p))
        else:
            raise TypeError('invalid argument: list or dictionnary expected')