From 36f2ed431d502d3e52a78b02fd0e0acd0a8564eb Mon Sep 17 00:00:00 2001
From: Lukas Riedel <34276446+peanutfun@users.noreply.github.com>
Date: Thu, 17 Aug 2023 11:52:02 +0200
Subject: [PATCH] Fix mutable default values in ImpactFreqCurve

---
 climada/engine/impact.py | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/climada/engine/impact.py b/climada/engine/impact.py
index 84840c613..39cd327b1 100644
--- a/climada/engine/impact.py
+++ b/climada/engine/impact.py
@@ -1854,10 +1854,10 @@ class ImpactFreqCurve():
     """dictionary of tags of exposures, impact functions set and
         hazard: {'exp': Tag(), 'impf_set': Tag(), 'haz': Tag()}"""
 
-    return_per : np.array = np.array([])
+    return_per : np.ndarray = field(default_factory=lambda: np.empty(0))
     """return period"""
 
-    impact : np.array = np.array([])
+    impact : np.ndarray = field(default_factory=lambda: np.empty(0))
     """impact exceeding frequency"""
 
     unit : str = ''