code: def _add(self, other, lhs_negative, rhs_negative):
      if cupy.isscalar(other):
          if other == 0:
              if lhs_negative:
                  return -self
              else:
                  return self.copy()
          else:
              raise NotImplementedError(
                  "adding a nonzero scalar to a sparse matrix is not "
                  "supported"
              )
      elif _base.isspmatrix(other):
          alpha = -1 if lhs_negative else 1
          beta = -1 if rhs_negative else 1
          return self._add_sparse(other, alpha, beta)
      elif _base.isdense(other):
          if lhs_negative:
              if rhs_negative:
                  return -self.todense() - other
              else:
                  return other - self.todense()
          else:
              if rhs_negative:
                  return self.todense() - other
              else:
                  return self.todense() + other
      else:
          return NotImplemented
  
imports: import string
  import warnings
  import numpy
  import cupy
  import cupyx
  from cupy import _core
  from cupy._core import _scalar
  from cupy._creation import basic
  from cupyx.scipy.sparse import _base
  from cupyx.scipy.sparse import _coo
  from cupyx.scipy.sparse import _data
  from cupyx.scipy.sparse import _sputils
  from cupyx.scipy.sparse import _util
  from cupyx.scipy.sparse import _index
label_desc: Use image node_id 6 for calling the _compressed_sparse_matrix obj's underlying member method code with example usage: obj._add(other, lhs_negative, rhs_negative) and returns: self, unknown, self, NotImplemented, unknown, unknown, unknown, unknown