fix regressions

Author: Conengmo

folium/features.py

@@ -1446,7 +1446,7 @@ def __init__(
         columns: Optional[Sequence[Any]] = None,
         key_on: Optional[str] = None,
         bins: Union[int, Sequence[float]] = 6,
-        fill_color: str = "blue",
+        fill_color: Optional[str] = None,
         nan_fill_color: str = "black",
         fill_opacity: float = 0.6,
         nan_fill_opacity: Optional[float] = None,

folium/vector_layers.py

@@ -325,7 +325,7 @@ class Circle(Marker):
 
     def __init__(
         self,
-        location: Sequence[float],
+        location: Optional[Sequence[float]] = None,
         radius: float = 50,
         popup: Union[Popup, str, None] = None,
         tooltip: Union[Tooltip, str, None] = None,