Remove conditional as we know these args are always present

nilmdb/cmdline/extract.py

@@ -41,9 +41,8 @@ def setup(self, sub):
     return cmd
 
 def cmd_extract_verify(self):
-    if self.args.start is not None and self.args.end is not None:
-        if self.args.start > self.args.end:
-            self.parser.error("start is after end")
+    if self.args.start > self.args.end:
+        self.parser.error("start is after end")
 
     if self.args.binary:
         if (self.args.bare or self.args.annotate or self.args.markup or