code: def count_nonzero(self):
      return sum(np.count_nonzero(rowvals) for rowvals in self.data)
  
imports: from bisect import bisect_left
  import numpy
  from ._matrix import spmatrix
  from ._base import _spbase, sparray, issparse
  from ._index import IndexMixin, INT_TYPES, _broadcast_arrays
  from ._sputils import getdtype, isshape, isscalarlike, upcast_scalar, check_shape, check_reshape_kwargs
  from .None import _csparsetools
label_desc: Use image node_id 7 for calling the _lil_base obj's underlying member method code with example usage: obj.count_nonzero() and returns: sum