code: def to_str(self, obj):
      return "".join(str(obj).split())
  
file_path: qlib/tests/misc/test_sepdf.py
imports: import unittest
  import numpy
  import pandas
  from qlib.contrib.data.utils.sepdf import SepDataFrame
label_desc: Use image node_id 1 for calling the SepDF obj's underlying member method code with example usage: obj.to_str(obj) and returns: str