FIX: import local cached_property if standard does not exist

Author: giovaniceotto

rocketpy/Flight.py

@@ -9,7 +9,6 @@
 import math
 import time
 import warnings
-from functools import cached_property
 
 import matplotlib.pyplot as plt
 import numpy as np
@@ -18,6 +17,11 @@
 
 from .Function import Function
 
+try:
+    from functools import cached_property
+except ImportError:
+    from .tools import cached_property
+
 
 class Flight:
     """Keeps all flight information and has a method to simulate flight.