There are several validation functions that are defined. These functions take a single input value and check if it matches a certain pattern using regular expressions. If the input value is invalid, the function throws a ValidationError with an error message describing the problem.
The validation functions are:
validateName(name): checks if name contains only letters (upper or lower case).validatePassword(password): checks if password is not empty and has a length of at least 6 characters.validateConfirmPassword(password): checks if password matches the password entered in the password field. This function is called when the user submits a form with a password and confirm password fields.validateEmail(email): checks if email has a valid email format.validateUsername(username): checks if username contains only letters, digits, dots and underscores.validateDay(day): checks if day is a number between 0 and 99.validateYear(year): checks if year is a four-digit number.validatePhoneNumber(phoneNumber): checks if phoneNumber is a valid phone number. This function supports both formatted and non-formatted phone numbers.