@classmethod
def _size_from_header(cls, header):
    """
        Get the size of each columns from the header.

        :param dict header:
            The header template we have to get the size from.

        :return: The maximal size of the each data to print.
        :rtype: list
        """
    result = []
    for data in header:
        result.append(header[data])
    return result
