code: def time_write(self, num_cols):
      out = pa.BufferOutputStream()
      pq.write_table(self.table, out)
  
imports: import shutil
  import tempfile
  from pandas.util.testing import rands
  import numpy
  import pandas
  import pyarrow
label_desc: Use image node_id 2 for calling the ParquetManyColumns obj's underlying member method code with example usage: obj.time_write(num_cols) without return types