code: def open_font(self, name):
          
          fid = self.display.allocate_resource_id()
          ec = error.CatchError(error.BadName)
  
          request.OpenFont(display = self.display,
                           onerror = ec,
                           fid = fid,
                           name = name)
          self.sync()
  
          if ec.get_error():
              self.display.free_resource_id(fid)
              return None
          else:
              cls = self.display.get_resource_class('font', fontable.Font)
              return cls(self.display, fid, owner = 1)
docs: Open the font identifed by the pattern name and return its
          font object. If name does not match any font, None is returned.