How to use the nglview.NGLWidget function in nglview

geom : :obj:`mdtraj.Trajectory` object or str with a filename to anything that :obj:`mdtraj` can read

    ngl_wdg : an already instantiated widget to add the geom, default is None

    n_small : if the geometry has less than n_small residues, force a "ball and stick" represenation


    :return: :nglview.widget object
    """

    if isinstance(geom, str):
        geom = _md.load(geom)

    if ngl_wdg is None:
        if geom is None:
            ngl_wdg = _nglview.NGLWidget()
        else:
            ngl_wdg = _nglview.show_mdtraj(geom)
    else:
        ngl_wdg.add_trajectory(geom)

    # Let' some customization take place
    ## Do we need a ball+stick representation?
    if geom is not None:
        if geom.top.n_residues < n_small:
            for ic in range(len(ngl_wdg._ngl_component_ids)):
                # TODO FIND OUT WHY THIS FAILS FOR THE LAST REPRESENTATION
                #print("removing reps for component",ic)
                ngl_wdg.remove_cartoon(component=ic)
                ngl_wdg.clear_representations(component=ic)
                ngl_wdg.add_ball_and_stick(component=ic)

import nglview as nv
        else:
            raise EnvironmentError('Unable to display structure - not running in a Jupyter notebook environment')

        if not self.structure_file:
            raise ValueError("Structure file not loaded")

        only_chains = ssbio.utils.force_list(only_chains)
        to_show_chains = '( '
        for c in only_chains:
            to_show_chains += ':{} or'.format(c)
        to_show_chains = to_show_chains.strip(' or ')
        to_show_chains += ' )'

        if self.file_type == 'mmtf' or self.file_type == 'mmtf.gz':
            view = nv.NGLWidget()
            view.add_component(self.structure_path)
        else:
            view = nv.show_structure_file(self.structure_path, gui=gui)

        if recolor:
            view.clear_representations()
            if only_chains:
                view.add_cartoon(selection='{} and (not hydrogen)'.format(to_show_chains), color='silver', opacity=opacity)
            else:
                view.add_cartoon(selection='protein', color='silver', opacity=opacity)
        elif only_chains:
            view.clear_representations()
            view.add_cartoon(selection='{} and (not hydrogen)'.format(to_show_chains), color='silver', opacity=opacity)

        return view

"""
        try:  # If the graphical packages are not available, the GUI will not work.
            import nglview
        except ImportError:
            raise ImportError("The package nglview needs to be installed for the plot3d() function!")
        # Always visualize the parent basis
        parent_basis = self.get_parent_basis()
        if select_atoms is None:
            select_atoms = np.array(len(parent_basis)*[True])
        else:
            select_atoms = np.array(select_atoms)
            if custom_array is not None:
                custom_array = custom_array[select_atoms]
        struct = nglview.TextStructure(self._ngl_write_structure(parent_basis.get_chemical_symbols()[select_atoms],
                                                                 self.positions[select_atoms], self.cell, custom_array=custom_array))
        view = nglview.NGLWidget(struct)
        if spacefill:
            if color_scheme is None and custom_array is not None:
                color_scheme = 'occupancy'
            elif color_scheme is None:
                color_scheme = 'element'
            view.add_spacefill(radius_type='vdw', color_scheme=color_scheme, radius=particle_size)
            # view.add_spacefill(radius=1.0)
            view.remove_ball_and_stick()
        else:
            view.add_ball_and_stick()
        if show_cell:
            if parent_basis.cell is not None:
                view.add_unitcell()
        if custom_3darray is not None:
            for arr, pos in zip(custom_3darray[select_atoms], self.positions[select_atoms]):
                view.shape.add_arrow(list(pos), list(pos+arr), list(0.5*arr/np.linalg.norm(arr)+0.5), 0.2)

nglview.NGLWidget
            A nglview view of the molecule

        """
        if not which_import("nglview", return_bool=True):
            raise ModuleNotFoundError(
                f"Python module nglwview not found. Solve by installing it: `conda install -c conda-forge nglview`"
            )  # pragma: no cover

        import nglview as nv  # type: ignore

        if ngl_kwargs is None:
            ngl_kwargs = {}

        structure = nv.TextStructure(self.to_string("nglview-sdf"), ext="sdf")
        widget = nv.NGLWidget(structure, **ngl_kwargs)
        return widget

warnings.warn('custom_array is deprecated. Use scalar_field instead', DeprecationWarning)
            scalar_field = custom_array
        if custom_3darray is not None:
            warnings.warn('custom_3darray is deprecated. Use vector_field instead', DeprecationWarning)
            vector_field = custom_3darray
        # Always visualize the parent basis
        parent_basis = self.get_parent_basis()
        if select_atoms is None:
            select_atoms = np.array(len(parent_basis)*[True])
        else:
            select_atoms = np.array(select_atoms)
            if scalar_field is not None:
                scalar_field = scalar_field[select_atoms]
        struct = nglview.TextStructure(self._ngl_write_structure(parent_basis.get_chemical_symbols()[select_atoms],
                                                                 self.positions[select_atoms], self.cell, scalar_field=scalar_field))
        view = nglview.NGLWidget(struct)
        if spacefill:
            if color_scheme is None and scalar_field is not None:
                color_scheme = 'occupancy'
            elif color_scheme is None:
                color_scheme = 'element'
            #view.add_spacefill(radius_type='vdw', color_scheme=color_scheme, radius=particle_size)
            for elem, num in set(list(zip(parent_basis.get_chemical_symbols(), parent_basis.get_atomic_numbers()))):
                view.add_spacefill(selection='#'+elem, radius_type='vdw', color_scheme='element', radius=particle_size*(0.2+0.1*np.sqrt(num)))
            # view.add_spacefill(radius=1.0)
            view.remove_ball_and_stick()
        else:
            view.add_ball_and_stick()
        if show_cell:
            if parent_basis.cell is not None:
                view.add_unitcell()
        if vector_color is None and vector_field is not None: