Define a new private method within IntegerWithBase called toAlphaNumDigit() that takes an integer value as an argument and returns a char representing the digit. For argument values between 0 and 9, the method should simply return the unicode value for that argument (i. e., a char value between 48 and 57). For argument values greater than or equal to 10, the method should return unicode values corresponding to a lower-case letter in the alphabet(i. e., a char value between 97 and 122). Thus, the statement toAlphaNumDigit(15);, for example, should return the char value 102, which corresponds to the letter "f".