Read & Search lines of a file

gistfile1.txt

fin = inputFile
fout = open('logfile.txt'), 'w')
flag = False

with open(fin, 'r') as infile:
  content = infile.readline()
  if content.startwith("diff --"):
    content2 = infile.readline() # read next line and see if it has keyword
    if content2.__contains__("keyword"):
      fout.write(content)
      cout.floush()