Update pwrball.py - handle excpetion when avoid.cvs file does not exist.

pwrball.py

@@ -35,13 +35,17 @@ def main():
     logging.basicConfig(level=logging.INFO, format = "[%(levelname)s] (%(threadName)-10s) %(message)s",)
 
     avoid = []
-    with open("avoid.csv", "r") as f:
-      reader = csv.reader(f)
-      for row in reader:
-        introw = []
-        for num in row:
-          introw.append(int(num))
-        avoid.append(introw)
+
+    try:
+        with open("avoid.csv", "r") as f:
+          reader = csv.reader(f)
+          for row in reader:
+            introw = []
+            for num in row:
+              introw.append(int(num))
+            avoid.append(introw)
+    except FileNotFoundError:
+        pass
 
     for item in avoid:
       logging.debug("before: %s", item)