Validates the provided settings.

        * Checks ``inherit_image`` format.
        * Checks ``use_registry_name`` format.
        * Checks that ``apt_dependencies`` is not set when ``inherit_image`` is set.

        :raise ArcaMisconfigured: If some of the settings aren't valid.

def validate_configuration(self):
        """
        Validates the provided settings.

        * Checks ``inherit_image`` format.
        * Checks ``use_registry_name`` format.
        * Checks that ``apt_dependencies`` is not set when ``inherit_image`` is set.

        :raise ArcaMisconfigured: If some of the settings aren't valid.
        """
        super().validate_configuration()

        if self.inherit_image is not None:
            try:
                assert len(str(self.inherit_image).split(":")) == 2
            except (ValueError, AssertionError):
                raise ArcaMisconfigured(f"Image '{self.inherit_image}' is not a valid value for the 'inherit_image'"
                                        f"setting")

        if self.inherit_image is not None and self.get_dependencies() is not None:
            raise ArcaMisconfigured("An external image is used as a base image, "
                                    "therefore Arca can't install dependencies.")

        if self.use_registry_name is not None:
            try:
                assert 2 >= len(str(self.inherit_image).split("/")) <= 3
            except ValueError:
                raise ArcaMisconfigured(f"Registry '{self.use_registry_name}' is not valid value for the "
                                        f"'use_registry_name' setting.")