code: public static BitVector fromBitSet(BitSet bitSet, int size) {
  		if (bitSet == null) throw new IllegalArgumentException();
  		if (size < 0) throw new IllegalArgumentException();
  		final int length = bitSet.length();
  		return fromBitSetImpl(bitSet, size, length);
  	}
docs: Creates a {@link BitVector} by copying the bits in a <code>BitSet</code>.
  
  @param bitSet
  a <code>BitSet</code>
  @param size
  the size of {@link BitVector} to create, in bits
  @return a bit vector containing the bits of the bit set.
  @see Bits#asStore(BitSet, int)