code: def get_atom(value):
      
      atom = Atom()
      if value and value[0] in CFWS_LEADER:
          token, value = get_cfws(value)
          atom.append(token)
      if value and value[0] in ATOM_ENDS:
          raise errors.HeaderParseError(
              "expected atom but found '{}'".format(value))
      token, value = get_atext(value)
      atom.append(token)
      if value and value[0] in CFWS_LEADER:
          token, value = get_cfws(value)
          atom.append(token)
      return atom, value
docs: atom = [CFWS] 1*atext [CFWS]