`Medium`	`Codewriting` 	`300`

Determine if the given character is a digit or not.

## Example

- For `symbol = '0'`, the output should be
`isDigit(symbol) = true`;

- For `symbol = '-'`, the output should be
`isDigit(symbol) = false`.

## Input/Output

- [execution time limit] 4 seconds (go)

- [input] char symbol

    A character which is either a digit or not.

    Guaranteed constraints: \
    `Given symbol is from ASCII table`.

- [output] boolean

    `true` if symbol is a digit, `false` otherwise.

## [Go] Syntax Tips

``` go
// Prints help message to the console
// Returns a string
func helloWorld(name string) string {
    fmt.Printf("This prints to the console when you Run Tests");
    return "Hello, " + name;
}
```
