docs: def print_start_command(self, command):
          '''Set print command
          
          Args:
              command: the type of command you desire.
          Returns:
              None
          Raises:
              RuntimeError: Command too long.
          '''
          size = len(command)
          if size > 20:
              raise RuntimeError('Command too long')
          n1 = size/10
          n2 = size%10
          self.send('^PS'+chr(n1)+chr(n2)+command)