code: def _sat(lexer, varname):
      
      _expect_token(lexer, {KW_p})
      fmt = _expect_token(lexer, {KW_sat, KW_satx, KW_sate, KW_satex}).value
      nvars = _expect_token(lexer, {IntegerToken}).value
      return _sat_formula(lexer, varname, fmt, nvars)
docs: Return a DIMACS SAT.