code: def to_pickle(self, path, compression='infer',
                    protocol=pickle.HIGHEST_PROTOCOL):
          
          from pandas.io.pickle import to_pickle
          return to_pickle(self, path, compression=compression,
                           protocol=protocol)
docs: Pickle (serialize) object to file.
  
          Parameters
          ----------
          path : str
              File path where the pickled object will be stored.
          compression : {'infer', 'gzip', 'bz2', 'zip', 'xz', None}, \
          default 'infer'
              A string representing the compression to use in the output file. By
              default, infers from the file extension in specified path.
  
              .. versionadded:: 0.20.0
          protocol : int
              Int which indicates which protocol should be used by the pickler,
              default HIGHEST_PROTOCOL (see [1]_ paragraph 12.1.2). The possible
              values are 0, 1, 2, 3, 4. A negative value for the protocol
              parameter is equivalent to setting its value to HIGHEST_PROTOCOL.
  
              .. [1] https://docs.python.org/3/library/pickle.html
              .. versionadded:: 0.21.0
  
          See Also
          --------
          read_pickle : Load pickled pandas object (or any object) from file.
          DataFrame.to_hdf : Write DataFrame to an HDF5 file.
          DataFrame.to_sql : Write DataFrame to a SQL database.
          DataFrame.to_parquet : Write a DataFrame to the binary parquet format.
  
          Examples
          --------
          >>> original_df = pd.DataFrame({"foo": range(5), "bar": range(5, 10)})
          >>> original_df
             foo  bar
          0    0    5
          1    1    6
          2    2    7
          3    3    8
          4    4    9
          >>> original_df.to_pickle("./dummy.pkl")
  
          >>> unpickled_df = pd.read_pickle("./dummy.pkl")
          >>> unpickled_df
             foo  bar
          0    0    5
          1    1    6
          2    2    7
          3    3    8
          4    4    9
  
          >>> import os
          >>> os.remove("./dummy.pkl")