FIX: wrong operator in __sub__

Author: giovaniceotto

rocketpy/Function.py

@@ -2085,7 +2085,7 @@ def __sub__(self, other):
                 # Create new Function object
                 return Function(source, inputs, outputs, interpolation)
             else:
-                return Function(lambda x: (self.getValue(x) * other(x)))
+                return Function(lambda x: (self.getValue(x) - other(x)))
         # If other is Float except...
         except AttributeError:
             if isinstance(other, (float, int, complex)):