code: def loc(parser, start):
      """Returns a location object, used to identify the place in
      the source that created a given parsed object."""
      if parser.options["no_location"]:
          return None
  
      if parser.options["no_source"]:
          return Loc(start, parser.prev_end)
  
      return Loc(start, parser.prev_end, parser.source)
  
imports: from .None import ast
  from ..error import GraphQLSyntaxError
  from .lexer import Lexer, TokenKind, get_token_desc, get_token_kind_desc
  from .source import Source
label_desc: Use image node_id 3 for calling a global function with example usage: loc(parser, start) and returns: Loc, None, Loc