Openstack Horizon workflows

class Workflow(html.HTMLElement):
    """A Workflow is a collection of Steps. Its interface is very
    straightforward, but it is responsible for handling some very
    important tasks such as:

    * Handling the injection, removal, and ordering of arbitrary steps.

    * Determining if the workflow can be completed by a given user at runtime
      based on all available information.

    * Dispatching connections between steps to ensure that when context data
      changes all the applicable callback functions are executed.

    * Verifying/validating the overall data integrity and subsequently
      triggering the final method to complete the workflow.

    The ``Workflow`` class has the following attributes:

    .. attribute:: name

        The verbose name for this workflow which will be displayed to the user.
        Defaults to the class name.

    .. attribute:: slug

        The unique slug for this workflow. Required.

    .. attribute:: steps

        Read-only access to the final ordered set of step instances for
        this workflow.

    .. attribute:: default_steps

        A list of :class:`~horizon.workflows.Step` classes which serve as the
        starting point for this workflow's ordered steps. Defaults to an empty
        list (``[]``).

    .. attribute:: finalize_button_name

        The name which will appear on the submit button for the workflow's
        form. Defaults to ``"Save"``.

    .. attribute:: success_message

        A string which will be displayed to the user upon successful completion
        of the workflow. Defaults to
        ``"{{ workflow.name }} completed successfully."``

    .. attribute:: failure_message

        A string which will be displayed to the user upon failure to complete
        the workflow. Defaults to ``"{{ workflow.name }} did not complete."``

    .. attribute:: depends_on

        A roll-up list of all the ``depends_on`` values compiled from the
        workflow's steps.

    .. attribute:: contributions

        A roll-up list of all the ``contributes`` values compiled from the
        workflow's steps.

    .. attribute:: template_name

        Path to the template which should be used to render this workflow.
        In general the default common template should be used. Default:
        ``"horizon/common/_workflow.html"``.

    .. attribute:: entry_point

        The slug of the step which should initially be active when the
        workflow is rendered. This can be passed in upon initialization of
        the workflow, or set anytime after initialization but before calling
        either ``get_entry_point`` or ``render``.

    .. attribute:: redirect_param_name

        The name of a parameter used for tracking the URL to redirect to upon
        completion of the workflow. Defaults to ``"next"``.

    .. attribute:: object

        The object (if any) which this workflow relates to. In the case of
        a workflow which creates a new resource the object would be the created
        resource after the relevant creation steps have been undertaken. In
        the case of a workflow which updates a resource it would be the
        resource being updated after it has been retrieved.

    .. attribute:: wizard

        Whether to present the workflow as a wizard, with "prev" and "next"
        buttons and validation after every step.

    .. attribute:: fullscreen

        If the workflow is presented in a modal, and this attribute is
        set to True, then the ``fullscreen`` css class will be added so
        the modal can take advantage of the available screen estate.
        Defaults to ``False``.