mypy fix

Author: microslaw

pandas/core/sample.py

@@ -150,6 +150,7 @@ def sample(
         else:
             raise ValueError("Invalid weights: weights sum to zero")
 
+    if weights is not None:
         is_max_weight_dominating = size * weights.max() > 1
         if is_max_weight_dominating and not replace:
             raise ValueError(