code: def readlines(arg):
      
      fin = open(arg)
      lines_in = fin.readlines()
      fin.close()
      lines_out = []
      for line in lines_in:
          line = line.strip()
          if not line or line[0] == '#':
              continue
          lines_out.append(line)
      return lines_out
docs: Read lines from a file into a list.
  
      Removes whitespace and lines that start with '#'