'Read IERS-A table from a finals2000a.* file provided by USNO.
Parameters
file : str
full path to ascii file holding IERS-A data.
Defaults to ``iers.IERS_A_FILE``.
readme : str
full path to ascii file holding CDS-style readme.
Defaults to package version, ``iers.IERS_A_README``.
Returns
``IERS_A`` class instance'

@classmethod
def read(cls, file=None, readme=None):

    if (file is None):
        file = IERS_A_FILE
    if (readme is None):
        readme = IERS_A_README
    iers_a = Table.read(file, format=u'cds', readme=readme)
    table = cls._combine_a_b_columns(iers_a)
    table.meta[u'data_path'] = file
    table.meta[u'readme_path'] = readme
    return cls(table.filled())
