<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def set_widgets(self):
 """Set widgets on the Exposure Layer Origin Type tab."""

        # First, list available layers in order to check if there are
        # any available layers. Note This will be repeated in
        # set_widgets_step_fc_explayer_from_canvas because we need
        # to list them again after coming back from the Keyword Wizard.
        self.parent.step_fc_explayer_from_canvas.\
            list_compatible_canvas_layers()
        lst_wdg = self.parent.step_fc_explayer_from_canvas.lstCanvasExpLayers
        if lst_wdg.count():
            self.rbExpLayerFromCanvas.setText(tr(
                'I would like to use an exposure layer already loaded in QGIS'
                '\n'
                '(launches the %s for exposure if needed)'
            ) % self.parent.keyword_creation_wizard_name)
            self.rbExpLayerFromCanvas.setEnabled(True)
            self.rbExpLayerFromCanvas.click()
        else:
            self.rbExpLayerFromCanvas.setText(tr(

                'I would like to use an exposure layer already loaded in QGIS'
                '\n'
                '(no suitable layers found)'))
            self.rbExpLayerFromCanvas.setEnabled(False)
            self.rbExpLayerFromBrowser.click()

        # Set the memo labels on this and next (exposure) steps
        (_, exposure, _, exposure_constraints) = self.\
            parent.selected_impact_function_constraints()

        layer_geometry = exposure_constraints['name']

        text = (select_exposure_origin_question % (
            layer_geometry, exposure['name']))
        self.lblSelectExpLayerOriginType.setText(text)

        text = (select_explayer_from_canvas_question % (
            layer_geometry, exposure['name']))
        self.parent.step_fc_explayer_from_canvas.lblSelectExposureLayer.\
            setText(text)

        text = (select_explayer_from_browser_question % (
            layer_geometry, exposure['name']))
        self.parent.step_fc_explayer_from_browser.lblSelectBrowserExpLayer.\
            setText(text)

        # Set icon
        icon_path = get_image_path(exposure)
        self.lblIconIFCWExposureOrigin.setPixmap(QPixmap(icon_path))