+ """Exception class for when invalid units are specified"""
+
+RATES = {
+ 'uphill': {'rate': 4, 'direction': '↑'},
+ 'flat': {'rate': 6, 'direction': '→'}, # or downhill on foot
+ 'downhill': {'rate': 10, 'direction': '↓'},
+ 'bushwhacking': {'rate': 2, 'direction': '↹'},
+}