def _to_bytes(nums):
    """
    Convert a list of 11-bit numbers to a bytearray.

    Args:
        nums (int[]): list of 11-bit numbers

    Returns:
        bytes: bytearray
    """
    buffer = 0
    num_of_bits = 0
    output = []
    for i in range(len(nums)):
        buffer |= nums[i] << num_of_bits
        num_of_bits += 11
        while num_of_bits >= 8:
            output.append(buffer & 255)
            buffer = buffer >> 8
            num_of_bits -= 8
    if num_of_bits != 0:
        output.append(buffer & 255)
    return bytes(output)
