<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def read_ligolw_flag(source, name=None, **kwargs):
 """Read a single `DataQualityFlag` from a LIGO_LW XML file """

    name = [name] if name is not None else None
    return list(read_ligolw_dict(source, names=name, **kwargs).values())[0]