code: def get_fws(value):
      
      newvalue = value.lstrip()
      fws = WhiteSpaceTerminal(value[:len(value)-len(newvalue)], 'fws')
      return fws, newvalue
docs: FWS = 1*WSP
  
      This isn't the RFC definition.  We're using fws to represent tokens where
      folding can be done, but when we are parsing the *un*folding has already
      been done so we don't need to watch out for CRLF.