import time def block(file,size=65536):     while True:         nb = file.read(size)         if not nb:            break         yield nb def getLineCount(filename):     with open(filename,"r",encoding="utf-8") as f:         return sum(line.count("\n") for line in block(f)) if __name__ == "__main__":     import sys     import os     if len(sys.argv) != 2:         print("error imput argument")         sys.exit(-1)     if not os.path.isfile(sys.argv[1]) :        print(sys.argv + " is not a file")        sys.exit(-1)     start_time = time.time()     print(getLineCount(sys.argv[1]))     print(time.time() - start_time ,"seconds")