@classmethod
def has_entry_in_register(cls, blok, entry, key):
    """ Return True if One Class exist in this blok for this entry

        :param blok: name of the blok
        :param entry: is the existing entry name
        :param key: is the existing key in the entry
        """
    if entry not in cls.loaded_bloks[blok]:
        return False
    if key not in cls.loaded_bloks[blok][entry]:
        return False
    return len(cls.loaded_bloks[blok][entry][key]['bases']) > 0
