def var_to_str(self, var: str) -> T.Optional[str]:
    if ((var in self.vars) and self.vars[var]):
        return self.vars[var][0]
    return None
def var_to_str(self, var: str) -> T.Optional[str]:
    if ((var in self.vars) and self.vars[var]):
        return self.vars[var][0]
    return None