def get_bits(value, start_index, end_index):
    """
    Returns a set of bit in position from start_index till end_index indexes(inclusively) from byte value
    :param value: integer positive value
    :param start_index: the number of the first bit which will be included to result;
    most-significant bit is considered on the left and has number 0.
    :param end_index: the number of the last bit which will be included to result,
    end_index should be greater than start_index; most-significant bit is considered on the left and has number 0.
    :return: set of bit in position from start_index till end_index indexes(inclusively) from byte value
    """
    mask = 2 ** (end_index - start_index + 1) - 1
    mask = mask << start_index
    return (value & mask) >> start_index