class_docstr: Query is used to build complex queries that have more parameters than just
  the query string. The query string is set in the constructor, and other
  options have setter functions.
  
  The setter functions return the query object, so they can be chained,
  i.e. `Query("foo").verbatim().filter(...)` etc.
docstr: Add field to return fields (Optional: add 'AS' name
  to the field).
code: def return_field(
      self, field: str, as_field: Optional[str] = None
  ) -> "Query":
      """Add field to return fields (Optional: add 'AS' name
      to the field)."""
      self._return_fields.append(field)
      if as_field is not None:
          self._return_fields += ("AS", as_field)
      return self
  
imports: from typing import List, Optional, Union
label_desc: Use image node_id 5 for calling the Query obj's underlying member method code with example usage: obj.return_field(field, as_field) and returns: self