def _cnf(lexer, varname):
    """Return a DIMACS CNF."""
    _expect_token(lexer, {KW_p})
    _expect_token(lexer, {KW_cnf})
    nvars = _expect_token(lexer, {IntegerToken}).value
    nclauses = _expect_token(lexer, {IntegerToken}).value
    return _cnf_formula(lexer, varname, nvars, nclauses)
def _cnf ( lexer , varname ) : _expect_token ( lexer , { KW_p } ) _expect_token ( lexer , { KW_cnf } ) nvars = _expect_token ( lexer , { IntegerToken } ) . value nclauses = _expect_token ( lexer , { IntegerToken } ) . value return _cnf_formula ( lexer , varname , nvars , nclauses )
Return a DIMACS CNF.