If Statement not working Python while using nmap

I'm having some trouble getting my if statement to work properly. At the end of the iplist.txt there is an empty line that I don't want to run, but for some reason, it's still running. I tried removing the last line of the file but it only removes the last legit line and not the blank line, I even tried removing spaces, empty lines, and null lines but it still would run with a line. And the weirdest part is that the blank runs both in the if block and the else block.

 with open ("iplist.txt", "r") as file:
     filecontents = file.read()
     for line in filecontents.split('\n'):
      filename = (line) + ".txt "
      command = "nmap -O -oG " + ".\\ips\\" + (filename) + (line)
      print(command)
      print(filename)
      strlen = int (len(filename))
      print(strlen)
      compareline = line[:4]
      print(compareline)
      if compareline == beginline: #beginline is declared as 10.9 earlier in the file
       print("Testing 1..2...")
       os.system(command)
       filenameforos = (line + ".txt")
       #detailedosdetection = open(filenameforos)
       #next(filecontents)
      else:
       print("Testing...")
       del line
       #next(StopIteration)

Here are the contents of iplist.txt

10.9.10.38
10.9.10.45
10.9.11.10
#extra line