Made BokehRenderer.server_doc method more general

holoviews/plotting/bokeh/renderer.py

@@ -17,7 +17,7 @@
 
 from ...core import Store, HoloMap
 from ..comms import JupyterComm, Comm
-from ..plot import GenericElementPlot
+from ..plot import GenericElementPlot, Plot
 from ..renderer import Renderer, MIME_TYPES
 from .widgets import BokehScrubberWidget, BokehSelectionWidget, BokehServerWidgets
 from .util import compute_static_patch, serialize_json, attach_periodic, bokeh_version
@@ -155,18 +155,23 @@ def show_callback():
         return server
 
 
-    def server_doc(self, plot, doc=None):
+    @bothmethod
+    def server_doc(self_or_cls, obj, doc=None):
         """
-        Get server document.
+        Get a bokeh Document with the plot attached. May supply
+        an existing doc, otherwise bokeh.io.curdoc() is used to
+        attach the plot to the global document instance.
         """
         if doc is None:
             doc = curdoc()
+        if not isinstance(plot, (Plot, BokehServerWidgets)):
+            renderer = self_or_cls.instance(mode='server')
+            plot, _ =  renderer._validate(plot, 'auto')
         root = plot.state
         if isinstance(plot, BokehServerWidgets):
             plot = plot.plot
         plot.document = doc
-        plot.traverse(lambda x: attach_periodic(plot),
-                      [GenericElementPlot])
+        plot.traverse(lambda x: attach_periodic(x), [GenericElementPlot])
         doc.add_root(root)
         return doc