code: def document_is_multiline_python(document):
      
      def ends_in_multiline_string():
          """
          ``True`` if we're inside a multiline string at the end of the text.
          """
          delims = _multiline_string_delims.findall(document.text)
          opening = None
          for delim in delims:
              if opening is None:
                  opening = delim
              elif delim == opening:
                  opening = None
          return bool(opening)
  
      if '\n' in document.text or ends_in_multiline_string():
          return True
  
      def line_ends_with_colon():
          return document.current_line.rstrip()[-1:] == ':'
  
      # If we just typed a colon, or still have open brackets, always insert a real newline.
      if line_ends_with_colon() or \
              (document.is_cursor_at_the_end and
               has_unclosed_brackets(document.text_before_cursor)) or \
              document.text.startswith('@'):
          return True
  
      # If the character before the cursor is a backslash (line continuation
      # char), insert a new line.
      elif document.text_before_cursor[-1:] == '\\':
          return True
  
      return False
docs: Determine whether this is a multiline Python document.