code: public void setDataType(com.google.api.ads.admanager.axis.v201902.CustomFieldDataType dataType) {
          this.dataType = dataType;
      }
docs: Sets the dataType value for this CustomField.
  
  @param dataType   * The type of data this custom field contains. This attribute
  is read-only
  if there exists a {@link CustomFieldValue} for this
  field.