code: def get_proficiency_admin_session_for_objective_bank(self, objective_bank_id=None):
          
          if not objective_bank_id:
              raise NullArgument
          if not self.supports_proficiency_admin():
              raise Unimplemented()
          try:
              from . import sessions
          except ImportError:
              raise OperationFailed()
          try:
              session = sessions.ProficiencyAdminSession(objective_bank_id, runtime=self._runtime)
          except AttributeError:
              raise OperationFailed()
          return session
docs: Gets the OsidSession associated with the proficiency
          administration service for the given objective bank.
  
          arg:    objectiveBankId (osid.id.Id): the Id of the
                  ObjectiveBank
          return: (osid.learning.ProficiencyAdminSession) - a
                  ProficiencyAdminSession
          raise:  NotFound - no objective bank found by the given Id
          raise:  NullArgument - objectiveBankId is null
          raise:  OperationFailed - unable to complete request
          raise:  Unimplemented - supports_proficiency_admin() or
                  supports_visible_federation() is false
          compliance: optional - This method must be implemented if
                      supports_proficiency_admin() and
                      supports_visible_federation() are true