Revokes an approval for a given token.

  This method requires raw datastore access to manipulate approvals directly.

  Args:
    aff4_path: The aff4_path or client id the approval should be created for.
    token: The token that should be revoked.

def ApprovalRevokeRaw(aff4_path, token):
  """Revokes an approval for a given token.

  This method requires raw datastore access to manipulate approvals directly.

  Args:
    aff4_path: The aff4_path or client id the approval should be created for.
    token: The token that should be revoked.
  """
  try:
    urn = rdf_client.ClientURN(aff4_path)
  except type_info.TypeValueError:
    urn = rdfvalue.RDFURN(aff4_path)

  approval_urn = aff4.ROOT_URN.Add("ACL").Add(urn.Path()).Add(
      token.username).Add(utils.EncodeReasonString(token.reason))

  super_token = access_control.ACLToken(username="raw-approval-superuser")
  super_token.supervisor = True

  approval_request = aff4.FACTORY.Open(
      approval_urn, mode="rw", token=super_token)
  approval_request.DeleteAttribute(approval_request.Schema.APPROVER)
  approval_request.Close()