bytearray index out of range - Python snap7

Question

I am using python snap7 to communicate data between PLCs and am having trouble reading from an integer. The snap7 get_int function works with the following parameters (byteArray, byteIndex). However, when I pass the bytearray into the function it gives me the following error:

data[1] = data[1] & 0xff
IndexError: bytearray index out of range

I was wondering what is resulting in the byte index of being out of range, here is the get_int function as a part of the library:

def get_int(bytearray_: bytearray, byte_index: int) -> int:
    """Get int value from bytearray.

    Notes:
        Datatype `int` in the PLC is represented in two bytes

    Args:
        bytearray_: buffer to read from.
        byte_index: byte index to start reading from.

    Returns:
        Value read.

    Examples:
        >>> data = bytearray([0, 255])
        >>> snap7.util.get_int(data, 0)
            255
    """
    data = bytearray_[byte_index:byte_index + 2]
    data[1] = data[1] & 0xff
    data[0] = data[0] & 0xff
    packed = struct.pack('2B', *data)
    value = struct.unpack('>h', packed)[0]
    return value

Also, here is the snap7 docs:

https://python-snap7.readthedocs.io/en/latest/_modules/snap7/util.html