Move if statement in convert_coordinate() to avoid unnecessary division operation

lemi2seed/utils.py

@@ -101,16 +101,16 @@ def check_serial_number(serial_number: str, equipment: str) -> bool:
 
 def convert_coordinate(coordinate, hemisphere):
     """Convert coordinates outputted by LEMI to decimal degrees."""
+    if hemisphere not in ['N', 'S', 'E', 'W']:
+        logger.error("Unexpected hemisphere - {} - listed in data file!"
+                     .format(hemisphere))
+        return None
     try:
         coordinate = float(coordinate) / 100
     except ValueError:
         logger.error("Failed to convert geographic coordinate - {} - to "
                      "decimal degrees!".format(coordinate))
         return None
-    if hemisphere not in ['N', 'S', 'E', 'W']:
-        logger.error("Unexpected hemisphere - {} - listed in data file!"
-                     .format(hemisphere))
-        return None
     return -coordinate if hemisphere in ["S", "W"] else coordinate