code: def instructions(self):
          
          if not self.is_block:
              raise ValueError('expected block value, got %s' % (self._kind,))
          it = ffi.lib.LLVMPY_BlockInstructionsIter(self)
          parents = self._parents.copy()
          parents.update(block=self)
          return _InstructionsIterator(it, parents)
docs: Return an iterator over this block's instructions.
          The iterator will yield a ValueRef for each instruction.