I'm' trying to build a function to the job because my data frames are in a list. This is the function that I am working on:

```
def lower(x):

        '''

        This function lowercase the entire Data Frame.

        '''

        for x in clean_lst:
            for x.columns in x:
                x.columns['i'].map(lambda i: i.lower())

```

It's not working like that!

This is the list of data frames:

```
clean_lst = [pop_movies, trash_movies]

```

I am planing to access the list like this:

```
lower = [pd.DataFrame(lower(x)) for x in clean_list] 
pop_movies = lower[0] 
trash_movies = lower[1]

```

HELP!!!