def _set_start_time(self, v, load=False):
    """
    Setter method for start_time, mapped from YANG variable /keychain/key/accept_lifetime/start_time (time-format-start)
    If this variable is read-only (config: false) in the
    source YANG file, then _set_start_time is considered as a private
    method. Backends looking to populate this variable should
    do so via calling thisObj._set_start_time() directly.
    """
    if hasattr(v, "_utype"):
      v = v._utype(v)
    try:
      t = YANGDynClass(v,base=RestrictedClassType(base_type=unicode, restriction_dict={'pattern': u'(([0-1][0-9]|2[0-3]):[0-5][0-9]:[0-5][0-9]\\|(0[1-9]|1[012])/(0[1-9]|[12][0-9]|3[01])/\\d{4})', 'length': [u'0..32']}), is_leaf=True, yang_name="start-time", rest_name="start-time", parent=self, path_helper=self._path_helper, extmethods=self._extmethods, register_paths=True, extensions={u'tailf-common': {u'info': u'enter start time in the format HH:MM:SS|MM/DD/YYYY', u'cli-drop-node-name': None}}, namespace='urn:brocade.com:mgmt:brocade-keychain', defining_module='brocade-keychain', yang_type='time-format-start', is_config=True)
    except (TypeError, ValueError):
      raise ValueError({
          'error-string': """start_time must be of a type compatible with time-format-start""",
          'defined-type': "brocade-keychain:time-format-start",
          'generated-type': """YANGDynClass(base=RestrictedClassType(base_type=unicode, restriction_dict={'pattern': u'(([0-1][0-9]|2[0-3]):[0-5][0-9]:[0-5][0-9]\\|(0[1-9]|1[012])/(0[1-9]|[12][0-9]|3[01])/\\d{4})', 'length': [u'0..32']}), is_leaf=True, yang_name="start-time", rest_name="start-time", parent=self, path_helper=self._path_helper, extmethods=self._extmethods, register_paths=True, extensions={u'tailf-common': {u'info': u'enter start time in the format HH:MM:SS|MM/DD/YYYY', u'cli-drop-node-name': None}}, namespace='urn:brocade.com:mgmt:brocade-keychain', defining_module='brocade-keychain', yang_type='time-format-start', is_config=True)""",
        })

    self.__start_time = t
    if hasattr(self, '_set'):
      self._set()