@functools.lru_cache<EOL>def accession(auth, label, project=None):
return list(experiments(auth, label, project))[<NUM_LIT:0>].id<EOL>
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