@classmethod
def describe(cls):
    """
        Prints in the console a table showing the key, the label and the extra
        of all the definitions inside the class

        :return: None
        """
    key_list = list(map(str, cls.keys())) + ['Key']
    max_ = max(list(map(len, key_list)))
    if max_ < 2:
        max_ = 2
    row_format = '{:>' + str(max_) + '}' + ' | {:} | {:}'
    headers = ['Key', 'Label', 'Extra']
    print('Class: ', cls.__name__)
    header_line = row_format.format(*headers)
    print(header_line)
    print('-' * (len(header_line) - 1))
    for item in cls:
        print(row_format.format(str(item.key), item.label, item.extra))
