code: def basis_ket_zero_outside_hs(cls, ops, kwargs):
      
      from qnet.algebra.core.state_algebra import ZeroKet
      ind, = ops
      hs = kwargs['hs']
      if isinstance(ind, int):
          if ind < 0 or (hs._dimension is not None and ind >= hs._dimension):
              return ZeroKet
      return ops, kwargs
docs: For ``BasisKet.create(ind, hs)`` with an integer label `ind`, return a
      :class:`ZeroKet` if `ind` is outside of the range of the underlying Hilbert
      space