How to use the visualqc.config.default_padding function in VisualQC

def init_layout(self, views, num_rows_per_view,
                    num_slices_per_view, padding=cfg.default_padding):

        self.views = views
        self.num_slices_per_view = num_slices_per_view
        self.num_rows_per_view = num_rows_per_view
        self.num_rows = len(self.views) * self.num_rows_per_view
        self.num_cols = int((len(self.views) * self.num_slices_per_view) / self.num_rows)
        self.padding = padding

def init_layout(self, views, num_rows_per_view,
                    num_slices_per_view, padding=cfg.default_padding):

        self.views = views
        self.num_slices_per_view = num_slices_per_view
        self.num_rows_per_view = num_rows_per_view
        self.num_rows = len(self.views) * self.num_rows_per_view
        self.num_cols = int((len(self.views) * self.num_slices_per_view) / self.num_rows)
        self.padding = padding

def init_layout(self, views, num_rows_per_view,
                    num_slices_per_view, padding=cfg.default_padding):

        self.views = views
        self.num_slices_per_view = num_slices_per_view
        self.num_rows_per_view = num_rows_per_view
        self.num_rows = len(self.views) * self.num_rows_per_view
        self.num_cols = int((len(self.views) * self.num_slices_per_view) / self.num_rows)
        self.padding = padding

def init_layout(self, views, num_rows_per_view,
                    num_slices_per_view, padding=cfg.default_padding):

        self.padding = padding
        self.views = views
        self.num_slices_per_view = num_slices_per_view
        self.num_rows_per_view = num_rows_per_view
        num_cols_volumetric = num_slices_per_view / num_rows_per_view
        num_rows_volumetric = len(self.views) * self.num_rows_per_view
        total_num_panels_vol = int(num_cols_volumetric * num_rows_volumetric)

        # surf vis generation happens at the beginning - no option to defer for user
        if not self.no_surface_vis and 'cortical' in self.vis_type:
            extra_panels_surface_vis = cfg.num_cortical_surface_vis
            extra_rows_surface_vis = 1
            self.volumetric_start_index = extra_panels_surface_vis
        else:
            extra_panels_surface_vis = 0

def init_layout(self, views, num_rows_per_view,
                    num_slices_per_view, padding=cfg.default_padding):

        plt.style.use('dark_background')

        # vmin/vmax are controlled, because we rescale all to [0, 1]
        self.display_params = dict(interpolation='none', aspect='equal',
                                   origin='lower', cmap='gray', vmin=0.0, vmax=1.0)
        self.figsize = cfg.default_review_figsize

        self.collage = Collage(view_set=views,
                               num_slices=num_slices_per_view, num_rows=num_rows_per_view,
                               display_params=self.display_params,
                               bounding_rect=cfg.bounding_box_review,
                               figsize=self.figsize)
        self.fig = self.collage.fig
        self.fig.canvas.set_window_title('VisualQC T1 MRI : {} {} '
                                         ''.format(self.in_dir, self.mri_name))

def overlay_images(qcw, mri, seg,
                   subject_id=None,
                   annot=None,
                   figsize=None,
                   padding=default_padding,
                   output_path=None):
    """Backend engine for overlaying a given seg on MRI with freesurfer label."""

    num_rows_per_view, num_slices_per_view, padding = check_params(qcw.num_rows, qcw.num_slices, padding)
    mri, seg = crop_to_seg_extents(mri, seg, padding)

    surf_vis = dict()  # empty - no vis to include
    # TODO broaden this to include subcortical structures as well
    if 'cortical' in qcw.vis_type:
        if qcw.in_dir is not None and subject_id is not None and qcw.out_dir is not None:
            surf_vis = make_vis_pial_surface(qcw.in_dir, subject_id, qcw.out_dir)
    num_surf_vis = len(surf_vis)

    # TODO calculation below is redundant, if surf vis does not fail
    # i.e. if num_surf_vis is fixed, no need to recompute for every subject
    num_views = len(qcw.views)

def init_layout(self,
                    view_set=cfg.defacing_view_set,
                    num_rows_per_view=cfg.defacing_num_rows_per_view,
                    num_slices_per_view=cfg.defacing_num_slices_per_view,
                    padding=cfg.default_padding):
        """initializes the layout"""

        plt.style.use('dark_background')

        # vmin/vmax are controlled, because we rescale all to [0, 1]
        self.display_params = dict(interpolation='none', aspect='equal',
                                   origin='lower', cmap='gray',
                                   vmin=0.0, vmax=1.0)
        self.figsize = cfg.default_review_figsize

        self.collage = Collage(view_set=view_set,
                               num_slices=num_slices_per_view,
                               num_rows=num_rows_per_view,
                               display_params=self.display_params,
                               bounding_rect=cfg.bbox_defacing_MRI_review,
                               figsize=self.figsize)

def init_layout(self, views, num_rows_per_view,
                    num_slices_per_view, padding=cfg.default_padding):

        self.views = views
        self.num_slices_per_view = num_slices_per_view
        self.num_rows_per_view = num_rows_per_view
        self.num_rows = len(self.views) * self.num_rows_per_view
        self.num_cols = int(
            (len(self.views) * self.num_slices_per_view) / self.num_rows)
        self.padding = padding