code: def write_data(self, output):
      format = "f" if self.is_float() else "d"
      for sequence in self.sequences:
          # write out each sequence in sparse format
          values = []
          indices = []
          sizes = []
          for sample in sequence:
              sizes.append(len(sample))
              sample.sort(key=lambda x: x[0])
              for index, value in sample:
                  indices.append(index)
                  values.append(value)
  
          output.write(
              struct.pack("<I", len(sequence))
          )  # number of samples in this sequence
          # nnz and indices have to be written out as signed ints, since
          # this is the index type of the CNTK sparse matrix
          output.write(
              struct.pack("<i", len(values))
          )  # total nnz count for this sequence
          self.write_floats(output, values)
          self.write_signed_ints(output, indices)
          self.write_signed_ints(output, sizes)
  
imports: import sys
  import argparse
  import struct
  import os
  from collections import OrderedDict
label_desc: Use image node_id 3 for calling the SparseConverter obj's underlying member method code with example usage: obj.write_data(output) without return types