isalnum() method checks whether all the characters of the string are alphanumeric or not.
In python, alphanumeric is a sequence of characters which consists of either alphabets (a-z or A-Z) or numbers (0 - 9).
Note: This method does not allow special characters: (space)!#%&? etc.
It does not take any parameter.
|True||If this string is an alphanumeric.|
|False||If this string is not an alphanumeric.|