code: function createCustomField($name, $type = 'string')
      {
          $queryParameters = array('type' => $type);
          $encodedName = urlencode(mb_convert_encoding($name, "UTF-8"));
          return $this->post("contacts/fields/custom/${encodedName}", "", $queryParameters);
      }
docs: Creates a custom contact field with the provided name and data type.
  
  @param string $name
  the name of the new field
  @param string $type
  the type of the new field. Valid values are 'string', 'integer', 'float', 'date' or 'boolean'.
  @return \em com_maileon_api_MaileonAPIResult
  the result object of the API call, with a com_maileon_api_contacts_Contact
  available at com_maileon_api_MaileonAPIResult::getResult()
  @throws com_maileon_api_MaileonAPIException
  if there was a connection problem or a server error occurred