pangrams hackerrank solution in python

ascii_array = []
def pangram(string):
    lower_string = string.lower()
    for i in range(len(lower_string)):
        ascii_array.append(ord(lower_string[i]))
    for i in range(97, 123):
        if i not in ascii_array:
            return 'Not Pangram'
    return 'Pangram'