# Write a Python program to Count the frequency of matrix row length # Python3 code to demonstrate working of# Row lengths counts# Using dictionary + loop  # initializing listtest_list = [[6, 3, 1], [8, 9], [2],              [10, 12, 7], [4, 11]]  # printing original listprint("The original list is : " + str(test_list))  res = dict()for sub in test_list:      # initializing incase of new length    if len(sub) not in res:        res[len(sub)] = 1      # increment in case of length present    else:        res[len(sub)] += 1  # printing resultprint("Row length frequencies : " + str(res))