How to use the kivymd.backgroundcolorbehavior.SpecificBackgroundColorBehavior function in kivymd

def on_tab_press(self, *args):
        par = self.parent_widget
        par.ids.tab_manager.current = self.name
        if par.previous_tab is not self:
            Animation(_label_font_size=sp(12), d=0.1).start(par.previous_tab.header)
            Animation(_current_color=par.previous_tab.header.theme_cls.disabled_hint_text_color, d=0.1).start(par.previous_tab.header)
            par.previous_tab.header.active = False
            self.header.active = True
        par.previous_tab = self

    def on_leave(self, *args):
        pass


class TabbedPanelBase(ThemableBehavior, SpecificBackgroundColorBehavior, BoxLayout):
    """
    A class that contains all variables a TabPannel must have
    It is here so I (zingballyhoo) don't get mad about the TabbedPannels not being DRY
    """
    tabs = ListProperty([])

    # Current tab name
    current = StringProperty(None)

    previous_tab = ObjectProperty(None)


class MDTabbedPanel(TabbedPanelBase):
    """ A tab panel that is implemented by delegating all tabs
        to a ScreenManager.
    """

class ColorSelector(MDIconButton):
    color_name = OptionProperty(
            'Indigo',
            options=['Red', 'Pink', 'Purple', 'DeepPurple', 'Indigo', 'Blue',
                     'LightBlue', 'Cyan', 'Teal', 'Green', 'LightGreen',
                     'Lime', 'Yellow', 'Amber', 'Orange', 'DeepOrange',
                     'Brown', 'Grey', 'BlueGrey'])

    def rgb_hex(self, col):
        return get_color_from_hex(colors[col][self.theme_cls.accent_hue])


class MDThemePicker(ThemableBehavior, FloatLayout, ModalView,
                    SpecificBackgroundColorBehavior,
                    RectangularElevationBehavior):
    pass


if __name__ == "__main__":
    from kivy.app import App
    from kivymd.theming import ThemeManager

    class ThemePickerApp(App):
        theme_cls = ThemeManager()

        def build(self):
            main_widget = Builder.load_string("""
#:import MDRaisedButton kivymd.button.MDRaisedButton
#:import MDThemePicker kivymd.theme_picker.MDThemePicker
FloatLayout:

AnchorLayout):
    text = StringProperty()
    owner = ObjectProperty()
    is_today = BooleanProperty(False)
    is_selected = BooleanProperty(False)

    def on_release(self):
        self.owner.set_selected_widget(self)


class WeekdayLabel(MDLabel):
    pass


class MDDatePicker(FloatLayout, ThemableBehavior, RectangularElevationBehavior,
                   SpecificBackgroundColorBehavior, ModalView):
    _sel_day_widget = ObjectProperty()
    cal_list = None
    cal_layout = ObjectProperty()
    sel_year = NumericProperty()
    sel_month = NumericProperty()
    sel_day = NumericProperty()
    day = NumericProperty()
    month = NumericProperty()
    year = NumericProperty()
    today = date.today()
    callback = ObjectProperty()
    background_color = ListProperty([0, 0, 0, 0.7])

    class SetDateError(Exception):
        pass

from kivy.lang import Builder
from kivy.properties import (ListProperty, ObjectProperty, OptionProperty,
                             StringProperty)
from kivy.uix.accordion import Accordion, AccordionItem
from kivy.uix.boxlayout import BoxLayout

from kivymd.backgroundcolorbehavior import SpecificBackgroundColorBehavior
from kivymd.list import OneLineListItem
from kivymd.theming import ThemableBehavior


class MDAccordionItemTitleLayout(ThemableBehavior, BoxLayout):
    pass


class MDAccordion(ThemableBehavior, SpecificBackgroundColorBehavior, Accordion):
    pass


class MDAccordionSubItem(OneLineListItem):
    parent_item = ObjectProperty()


class MDAccordionItem(ThemableBehavior, AccordionItem):
    title_theme_color = OptionProperty(None, allownone=True,
                                       options=['Primary', 'Secondary', 'Hint',
                                                'Error', 'Custom'])
    ''' Color theme for title text and  icon '''

    title_color = ListProperty(None, allownone=True)
    ''' Color for title text and icon if `title_theme_color` is Custom '''

class ColorSelector(MDIconButton):
    color_name = OptionProperty(
            'Indigo',
            options=['Red', 'Pink', 'Purple', 'DeepPurple', 'Indigo', 'Blue',
                     'LightBlue', 'Cyan', 'Teal', 'Green', 'LightGreen',
                     'Lime', 'Yellow', 'Amber', 'Orange', 'DeepOrange',
                     'Brown', 'Grey', 'BlueGrey'])

    def rgb_hex(self, col):
        return get_color_from_hex(colors[col][self.theme_cls.accent_hue])


class MDThemePicker(ThemableBehavior, FloatLayout, ModalView,
                    SpecificBackgroundColorBehavior,
                    RectangularElevationBehavior):
    pass


if __name__ == "__main__":
    from kivy.app import App
    from kivymd.theming import ThemeManager


    class ThemePickerApp(App):
        theme_cls = ThemeManager()

        def build(self):
            main_widget = Builder.load_string('''
#:import MDRaisedButton kivymd.button.MDRaisedButton
#:import MDThemePicker kivymd.theme_picker.MDThemePicker

opposite_colors: root.opposite_colors
            theme_text_color: 'Custom'
            text_color: root.specific_text_color
            text: root.title
            shorten: True
            shorten_from: 'right'
    BoxLayout:
        id: right_actions
        orientation: 'horizontal'
        size_hint_x: None
        padding: [0, (self.height - dp(48))/2]
''')


class Toolbar(ThemableBehavior, RectangularElevationBehavior,
              SpecificBackgroundColorBehavior, BoxLayout):
    left_action_items = ListProperty()
    """The icons on the left of the Toolbar.

    To add one, append a list like the following:

        ['icon_name', callback]

    where 'icon_name' is a string that corresponds to an icon definition and
     callback is the function called on a touch release event.
    """

    right_action_items = ListProperty()
    """The icons on the left of the Toolbar.

    Works the same way as :attr:`left_action_items`
    """

def __init__(self, **kwargs):
        super(SpecificBackgroundColorBehavior, self).__init__(**kwargs)
        if hasattr(self, 'theme_cls'):
            self.theme_cls.bind(primary_palette=self._update_specific_text_color)
            self.theme_cls.bind(accent_palette=self._update_specific_text_color)
            self.theme_cls.bind(theme_style=self._update_specific_text_color)
        self.bind(background_hue=self._update_specific_text_color)
        self.bind(background_palette=self._update_specific_text_color)
        self._update_specific_text_color(None, None)

md_bg_color: root.theme_cls.primary_color
    theme_text_color: 'Custom'
    text_color: root.specific_text_color

:
    # Defaults to 56-by-56 and a backround of the accent color according to
    # guidelines
    size: (dp(56), dp(56))
    md_bg_color: root.theme_cls.accent_color
    theme_text_color: 'Custom'
    text_color: root.specific_text_color
''')


class BaseButton(ThemableBehavior, ButtonBehavior,
                 SpecificBackgroundColorBehavior, AnchorLayout):
    '''
    Abstract base class for all MD buttons. This class handles the button's
    colors (disabled/down colors handled in children classes as those depend on
    type of button) as well as the disabled state.
    '''
    _md_bg_color_down = ListProperty(None, allownone=True)
    _md_bg_color_disabled = ListProperty(None, allownone=True)
    _current_button_color = ListProperty([0., 0., 0., 0.])
    theme_text_color = OptionProperty(None, allownone=True,
                                      options=['Primary', 'Secondary', 'Hint',
                                               'Error', 'Custom',
                                               'ContrastParentBackground'])
    text_color = ListProperty(None, allownone=True)
    opposite_colors = BooleanProperty(False)

    def __init__(self, **kwargs):