code: def __neg__(self):
      if self.dtype.kind == "b":
          raise NotImplementedError(
              "Negating a sparse boolean matrix is not" " supported."
          )
      new = self._dok_container(self.shape, dtype=self.dtype)
      new._dict.update((k, -self[k]) for k in self.keys())
      return new
  
imports: import itertools
  import numpy
  from ._matrix import spmatrix
  from ._base import _spbase, sparray, issparse
  from ._index import IndexMixin
  from ._sputils import isdense, getdtype, isshape, isintlike, isscalarlike, upcast, upcast_scalar, check_shape
label_desc: Use image node_id 30 for calling the _dok_base obj's underlying member method code with example usage: obj.__neg__() and returns: new