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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:

def accession(auth, label, project=None):
    '''
    Get the Accession ID for any Experiment label.

    Example:
        >>> import yaxil
        >>> auth = yaxil.XnatAuth(url='...', username='...', password='...')
        >>> yaxil.accession(auth, 'AB1234C')
        u'XNAT_E00001'

    :param auth: XNAT authentication
    :type auth: :mod:`yaxil.XnatAuth`
    :param label: XNAT Experiment label
    :type label: str
    :param project: XNAT Experiment Project
    :type project: str
    :returns: Accession ID
    :rtype: str
    '''
    return list(experiments(auth, label, project))[0].id