@internal<EOL><INDENT>def _loadFromHStream(self, dtype: HStream, bitAddr: int) -> int:<DEDENT>
ch = TransTmpl(dtype.elmType, <NUM_LIT:0>, parent=self, origin=self.origin)<EOL>self.children.append(ch)<EOL>return bitAddr + dtype.elmType.bit_length()<EOL>
Parse HUnion type to this transaction template instance

:return: address of it's end