code: def print_stmt(self, print_loc, stmt):
          
          stmt.keyword_loc = print_loc
          if stmt.loc is None:
              stmt.loc = print_loc
          else:
              stmt.loc = print_loc.join(stmt.loc)
          return stmt
docs: (2.6-2.7)
          print_stmt: 'print' ( [ test (',' test)* [','] ] |
                                '>>' test [ (',' test)+ [','] ] )