docs: def flush_print(*args, **kwargs):
      """
      Like print_function at python3, support flush, but not support file.
      :param sep: space by default
      :param end: '\\n' by default
      :param flush: True by default
  
       ::
  
          import time
          from torequests.utils import flush_print
  
          flush_print("=" * 10)
          for _ in range(10):
              time.sleep(0.2)
              flush_print("=", sep="", end="")
      """
      # PY2 raise SyntaxError for : def flush_print(*args, sep='', end=''):
      sep, end, flush = (
          kwargs.pop("sep", " "),
          kwargs.pop("end", "\n"),
          kwargs.pop("flush", 1),
      )
      string = sep.join((unicode(i) for i in args))
      sys.stdout.write("%s%s" % (string, end))
      if flush:
          sys.stdout.flush()