import Impact from climada.engine.impact

in order to avoid circular imports

climada/engine/cost_benefit.py

@@ -31,7 +31,7 @@
 from matplotlib.patches import FancyArrowPatch, Rectangle
 from tabulate import tabulate
 
-from climada.engine import Impact, ImpactFreqCurve
+from climada.engine.impact import Impact, ImpactFreqCurve
 from climada.engine.impact_calc import ImpactCalc
 
 LOGGER = logging.getLogger(__name__)

climada/engine/impact_calc.py

@@ -28,7 +28,7 @@
 from scipy import sparse
 
 from climada import CONFIG
-from climada.engine import Impact
+from climada.engine.impact import Impact
 
 LOGGER = logging.getLogger(__name__)