pub fn from_le_bytes(bytes: impl AsRef<[u8]>) -> StacksResult<Self> {
		let bytes = bytes.as_ref();

		if bytes.len() % 8 != 0 {
			return Err(StacksError::InvalidUintBytes(bytes.len()));
		}

		if bytes.len() / 8 != N {
			return Err(StacksError::InvalidUintBytes(bytes.len()));
		}

		let mut ret = [0u64; N];
		for i in 0..(bytes.len() / 8) {
			let mut next_bytes = [0u8; 8];
			next_bytes.copy_from_slice(&bytes[8 * i..(8 * (i + 1))]);

			let next = u64::from_le_bytes(next_bytes);

			ret[i] = next;
		}

		Ok(Self(ret))
	}
Build from a little-endian hex string (padding expected)
stacks-core/src/uint.rs