code: def optional_parameters(self):
      return self._optional_params
  
file_path: dipy/dipy/workflows/base.py
imports: import argparse
  import inspect
  from dipy.workflows.docstring_parser import NumpyDocString
label_desc: Use image node_id 12 for calling the IntrospectiveArgumentParser obj's underlying member method code with example usage: obj.optional_parameters() and returns: self