code: def coalesce(self, reduce: str = "add"):
      idx = self._col.new_full((self._col.numel() + 1,), -1)
      idx[1:] = self._sparse_sizes[1] * self.row() + self._col
      mask = idx[1:] > idx[:-1]
  
      if mask.all():  # Skip if indices are already coalesced.
          return self
  
      row = self.row()[mask]
      col = self._col[mask]
  
      value = self._value
      if value is not None:
          ptr = mask.nonzero().flatten()
          ptr = torch.cat([ptr, ptr.new_full((1,), value.size(0))])
          value = segment_csr(value, ptr, reduce=reduce)
  
      return SparseStorage(
          row=row,
          rowptr=None,
          col=col,
          value=value,
          sparse_sizes=self._sparse_sizes,
          rowcount=None,
          colptr=None,
          colcount=None,
          csr2csc=None,
          csc2csr=None,
          is_sorted=True,
          trust_data=True,
      )
  
imports: import warnings
  from typing import List, Optional, Tuple
  import torch
  from torch_scatter import scatter_add, segment_csr
  from torch_sparse.utils import Final, index_sort
label_desc: Use image node_id 27 for calling the SparseStorage obj's underlying member method code with example usage: obj.coalesce(reduce) and returns: SparseStorage, self