banner_grabber.py

class BannerGrabber:

  input_file = ""

  def __init__(self, input):
    self.input_file = input
    
  def run():
    with open(self.input_file) as f:
      for line in f:
        h, p = line.split
        grab_banner(h, p)
    
  def grab_banner(host, port)
    # code to get the banner

main.py

grabber = BannerGrabber("input.txt")
grabber.run()