In this kata, you'll be given an integer of range `0 <= x <= 99` and have to return that number spelt out in English. A few examples:
```python
name_that_number(4)   # returns "four"
name_that_number(19)  # returns "nineteen"
name_that_number(99)  # returns "ninety nine"
```
Words should be separated by only spaces and not hyphens. No need to validate parameters, they will always be in the range [0, 99]. Make sure that the returned String has no leading of trailing spaces. Good luck!
def name_that_number(num):
    num_str = str(num)
    word_num = ['zero', "one", "two", "three", "four", "five", "six", "seven", "eight", "nine", "ten", "eleven",
            "twelve", "thirteen", "fourteen", "fifteen", "sixteen", "seventeen", "eighteen", "nineteen"]
    word_units = ["twenty", "thirty", "forty", "fifty", "sixty", "seventy", "eighty", "ninety"]
        
    if num < 20:
        return word_num[num]
    else:   
        first_digit = int(num_str[0]) - 2
        second_digit = int(num_str[1]) 
        if second_digit == 0:
            return word_units[first_digit]
        else:   
            return word_units[first_digit] + ' ' + word_num[second_digit]
def name_that_number(num):
    num_str = str(num)
    word_num = ['zero', "one", "two", "three", "four", "five", "six", "seven", "eight", "nine", "ten", "eleven",
            "twelve", "thirteen", "fourteen", "fifteen", "sixteen", "seventeen", "eighteen", "nineteen"]
    word_units = ["twenty", "thirty", "forty", "fifty", "sixty", "seventy", "eighty", "ninety"]
        
    if num < 20:
        return word_num[num]
    else:   
        first_digit = int(num_str[0]) - 2
        second_digit = int(num_str[1]) 
        if second_digit == 0:
            return word_units[first_digit]
        else:   
            return word_units[first_digit] + ' ' + word_num[second_digit]