helper text for select material ui code example

Example: material ui select helper text

<FormControl className={classes.formControl} error>
  <InputLabel id="demo-simple-select-error-label">Name</InputLabel>
  <Select
    labelId="demo-simple-select-error-label"
    id="demo-simple-select-error"
    value={age}
    onChange={handleChange}
    >
    <MenuItem value={10}>Ten</MenuItem>
    <MenuItem value={20}>Twenty</MenuItem>
    <MenuItem value={30}>Thirty</MenuItem>
  </Select>
  <FormHelperText>Error</FormHelperText>
</FormControl>