'Grant an approval from approver to delegate.
Args:
client_id: ClientURN
delegate: username string of the user receiving approval.
reason: reason for approval request.
approver: username string of the user granting approval.'

def GrantClientApproval(self, client_id, delegate, reason='testing', approver='approver'):

    self.CreateAdminUser(approver)
    approver_token = access_control.ACLToken(username=approver)
    grantor = security.ClientApprovalGrantor(subject_urn=client_id, reason=reason, delegate=delegate, token=approver_token)
    grantor.Grant()
