How to use the nbconvert.exporters.python.PythonExporter function in nbconvert

def _tst_notebook(self, notebook_name):

        notebook_filename = os.path.abspath(os.path.join(
            self.this_file_directory, '..', '..', 'examples', notebook_name))

        with open(notebook_filename) as f:
            nb = nbformat.read(f, as_version=4)

        python_nb, metadata = export(PythonExporter, nb)

        # Remove magic lines manually
        python_nb = '\n'.join([
            line for line in python_nb.split('\n')
            if 'get_ipython().run_line_magic(' not in line
        ])

        exec(python_nb)

def nb_to_python(nb_path):
    """convert notebook to python script"""
    exporter = python.PythonExporter()
    output, resources = exporter.from_filename(nb_path)
    return output

def compile(Compiler, ast): 
        """Compile AST to bytecode using the an IPython compiler."""
        return (Compiler.ip and Compiler.ip.compile or CachingCompiler())(ast, Compiler.filename, 'exec')
            
    def ast_parse(Compiler, source, filename='', symbol='exec', lineno=0): 
        return ast.increment_lineno(super().ast_parse(source, Compiler.filename, 'exec'), lineno)



# In[4]:


if __name__ ==  '__main__':
    from pathlib import Path
    Path('../importnb/compiler_ipython.py').write_text(PythonExporter().from_filename('compiler_ipython.ipynb')[0])
    __import__('doctest').testmod()

return Compiler.ip.input_transformer_manager.transform_cell

    def compile(Compiler, ast):
        """Compile AST to bytecode using the an IPython compiler."""
        return (Compiler.ip and Compiler.ip.compile or CachingCompiler())(
            ast, Compiler.filename, "exec"
        )

    def ast_parse(Compiler, source, filename="", symbol="exec", lineno=0):
        return ast.increment_lineno(super().ast_parse(source, Compiler.filename, "exec"), lineno)


Compiler = IpythonCompiler


class IpythonPythonExporter(_PythonExporter):

    def from_file(self, file_stream, resources=None, **kw):
        return self.from_notebook_node(from_dict(load(file_stream)), resources, **kw)


PythonExporter = IpythonPythonExporter


if __name__ == "__main__":
    try:
        from .compile import export
    except:
        from compile import export
    export("compile_ipython.ipynb", "../importnb/compile_ipython.py")
    __import__("doctest").testmod()

def convert_notebook(self, name):
        """Converts a notebook into a python file."""
        exporter = nbconvert.exporters.python.PythonExporter()
        relative_path = self.convert_path(name)
        file_path = self.get_path("%s.ipynb" % relative_path)
        code = exporter.from_filename(file_path)[0]
        self.write_code(name, code)
        self.clean_code(name, [])