code: def to_glyphs_font_attributes(self, source, master, is_initial):
      
      if is_initial:
          _set_glyphs_font_attributes(self, source)
      else:
          _compare_and_merge_glyphs_font_attributes(self, source)
docs: Copy font attributes from `ufo` either to `self.font` or to `master`.
  
      Arguments:
      self -- The UFOBuilder
      ufo -- The current UFO being read
      master -- The current master being written
      is_initial -- True iff this the first UFO that we process