human
Solve the following python programming problem given the following code:
def get_fields(self, required_only = False, include_system = True) : 
    def _is_match(field) : 
        if ((required_only and (not field.is_required)) or ((not include_system) and is_system_key (field.slug))) : 
            return False 
return True 
return filter (_is_match, required_only.fields) 

    
    

    Fix the buggy line: return filter (_is_match, required_only.fields)
assistant
#Here is Python program to fix the buggy line: return filter (_is_match, required_only.

return filter (_is_match, self.fields)