Added backward compatibility for dict basemaps (#901)

* Added backward compatibility for dict basemaps

Signed-off-by: Kharude, Sachin <[email protected]>

* updated as per review comments

Signed-off-by: Kharude, Sachin <[email protected]>

Author: sackh

ipyleaflet/leaflet.py

@@ -42,20 +42,26 @@ def basemap_to_tiles(basemap, day=yesterday, **kwargs):
 
     Parameters
     ----------
-    basemap : class:`xyzservices.lib.TileProvider`
+    basemap : class:`xyzservices.lib.TileProvider` or Dict
         Basemap description coming from ipyleaflet.basemaps.
     day: string
         If relevant for the chosen basemap, you can specify the day for
         the tiles in the "%Y-%m-%d" format. Defaults to yesterday's date.
     kwargs: key-word arguments
         Extra key-word arguments to pass to the TileLayer constructor.
     """
-    url = basemap.build_url(time=day, **kwargs)
+    if isinstance(basemap, xyzservices.lib.TileProvider):
+        url = basemap.build_url(time=day)
+    elif isinstance(basemap, dict):
+        url = basemap.get("url", "")
+    else:
+        raise ValueError("Invalid basemap type")
+
     return TileLayer(
         url=url,
         max_zoom=basemap.get('max_zoom', 19),
         min_zoom=basemap.get('min_zoom', 1),
-        attribution=basemap.get('html_attribution', ''),
+        attribution=basemap.get('html_attribution', '') or basemap.get('attribution', ''),
         name=basemap.get('name', ''),
         **kwargs
     )