code: func (f *Field) FilterAttrTopN(n uint64, row *PQLRowQuery, attrName string, attrValues ...interface{}) *PQLRowQuery {
  	return f.filterAttrTopN(n, row, attrName, attrValues...)
  }
docs: // FilterAttrTopN creates a TopN query with the given item count, row, attribute name and filter values for that field
  // The attrName and attrValues arguments work together to only return Rows which have the attribute specified by attrName with one of the values specified in attrValues.