human
Solve the following python programming problem given the following code:
def enum(length, values, default = None) : 
    def make_enum_field(parent, **field_options) : 
        enum_field = intX (length, signed = False) (parent, ** field_options) 
        old_encode_fn = enum_field._encode_fn 
        old_decode_fn = enum_field._decode_fn 
        keys = { v : k for (k, v) in list (values.items ()) } 
        def encode_enum(key) : 
            if (key not in keys) : 
                raise ValueError (('%s is not a valid enum value' % key)) 
return old_encode_fn (keys [key]) 
def decode_enum(encoded) : 
            decoded_value = old_decode_fn (encoded) 
            if (decoded_value not in values) : 
                if (default is not None) : 
                    return default 
else : 
                    raise ValueError (('%d is not a valid enum value' % decoded_value)) 
return values [decoded_value] 
enum_field._encode_fn = encode_enum 
        enum_field._decode_fn = decode_enum 
        return enum_field 
return length 

    
    

    Fix the buggy line: return length
assistant
#Here is Python code to fix the buggy line: return length
.

return def make_enum_field(