code: function toCsvString()
      {
  
          // Generate standard field string
          $standard_fields = "{";
          if (isset($this->standard_fields)) {
              foreach ($this->standard_fields as $index => $value) {
                  $standard_fields .= $index . "=" . $value . ",";
              }
              $standard_fields = rtrim($standard_fields, ',');
          }
          $standard_fields .= "}";
  
          // Generate custom field string
          $customfields = "{";
          if (isset($this->custom_fields)) {
              foreach ($this->custom_fields as $index => $value) {
                  $customfields .= $index . "=" . $value . ",";
              }
              $customfields = rtrim($customfields, ',');
          }
          $customfields .= "}";
  
          $permission = "";
          if (isset($this->permission)) {
              $permission = $this->permission->getCode();
          }
  
          return $this->id
          . ";" . $this->email
          . ";" . $permission
          . ";" . $this->external_id
          . ";" . (($this->anonymous == true) ? "true" : "false")
          . ";" . $this->created
          . ";" . $this->updated
          . ";\"" . $standard_fields . "\""
          . ";\"" . $customfields . "\"";
      }
docs: CSV representation of this wrapper.
  
  @return \em string
  A csv version of the contact.