Frequency feature for multiple accounts

Now that you know how to create a frequency feature for one account or person, let's do the same for multiple accounts at once. The dataset trans contains transactions made by Alice and Bob. Create the frequency feature freq_channel based on the same column channel_cd as the previous exercise.

The dataset trans, the zoo and dplyr packages are already loaded. The function frequency_fun() that you have written in the previous exercise is available in your workspace.