def calculate_checksum(self, packet_no_checksum):
    b = [packet_no_checksum[i:(i + 2)] for i in range(0, len(packet_no_checksum), 2)]
    c = [int(i, 16) for i in b]
    d = (sum(c) % 256)
    return hex(d)[2:].zfill(2)
def calculate_checksum(self, packet_no_checksum):
    b = [packet_no_checksum[i:(i + 2)] for i in range(0, len(packet_no_checksum), 2)]
    c = [int(i, 16) for i in b]
    d = (sum(c) % 256)
    return hex(d)[2:].zfill(2)