Convert from BitArray to Byte

I have a BitArray with the length of 8, and I need a function to convert it to a byte. How to do it?

Specifically, I need a correct function of ConvertToByte:

BitArray bit = new BitArray(new bool[]
{
    false, false, false, false,
    false, false, false, true
});

//How to write ConvertToByte
byte myByte = ConvertToByte(bit);
var recoveredBit = new BitArray(new[] { myByte });
Assert.AreEqual(bit, recoveredBit);