parameters: (self, line, font_attr_segs=None)
docstring: Prepend (i.e., add to the front) a single line of text.
  
      Args:
        line: (str) The text to be added to the front.
        font_attr_segs: (list of tuples) Font attribute segments of the appended
          line.
docstring_summary: Prepend (i.e., add to the front) a single line of text.
docstring_tokens: Prepend ( i . e . add to the front ) a single line of text .
function: def prepend(self, line, font_attr_segs=None):
      """Prepend (i.e., add to the front) a single line of text.
  
      Args:
        line: (str) The text to be added to the front.
        font_attr_segs: (list of tuples) Font attribute segments of the appended
          line.
      """
  
      other = RichTextLines(line)
      if font_attr_segs:
        other.font_attr_segs[0] = font_attr_segs
      self._extend_before(other)
function_tokens: def prepend ( self , line , font_attr_segs = None ) : other = RichTextLines ( line ) if font_attr_segs : other . font_attr_segs [ 0 ] = font_attr_segs self . _extend_before ( other )