fix: fixed bool iterable issue

app.py

@@ -327,7 +327,7 @@ def _generate_chart(
     scatter_x: Optional[str],
     scatter_y: Optional[str],
     scatter_color: Optional[str],
-) -> Tuple[Optional[mpl_fig.Figure], Optional[mpl_fig.Figure], str]:
+) -> Tuple[Any, Any, str]:
     """Create a visualization based on user selections."""
     state = _ensure_state(state)
     try:
@@ -375,7 +375,7 @@ def _download_filtered(state) -> str:
     return temp.name
 
 
-def _download_chart(fig: Optional[mpl_fig.Figure]) -> str:
+def _download_chart(fig: Any) -> str:
     """Export the most recent chart to PNG."""
     if fig is None:
         raise ValueError("Generate a visualization before exporting.")