code: def tocoo(self, copy=False):
      num_rows, num_cols = self.shape
      num_offsets, offset_len = self.data.shape
      offset_inds = np.arange(offset_len)
  
      row = offset_inds - self.offsets[:, None]
      mask = row >= 0
      mask &= row < num_rows
      mask &= offset_inds < num_cols
      mask &= self.data != 0
      row = row[mask]
      col = np.tile(offset_inds, num_offsets)[mask.ravel()]
      idx_dtype = self._get_index_dtype(
          arrays=(self.offsets,), maxval=max(self.shape)
      )
      row = row.astype(idx_dtype, copy=False)
      col = col.astype(idx_dtype, copy=False)
      data = self.data[mask]
      # Note: this cannot set has_canonical_format=True, because despite the
      # lack of duplicates, we do not generate sorted indices.
      return self._coo_container(
          (data, (row, col)),
          shape=self.shape,
          dtype=self.dtype,
          copy=False,
      )
  
imports: import numpy
  from ._matrix import spmatrix
  from ._base import issparse, _formats, _spbase, sparray
  from ._data import _data_matrix
  from ._sputils import isshape, upcast_char, getdtype, get_sum_dtype, validateaxis, check_shape
  from ._sparsetools import dia_matvec
label_desc: Use image node_id 15 for calling the _dia_base obj's underlying member method code with example usage: obj.tocoo(copy) and returns: self