I have a function that creates a dataframe:

```
def function(date):
...
return dataframe

```

Now I want to put the dataframe values into a dictionary with the key being the date and the dataframe being the value:

```
d = {}
d[date] = dataframe

```

however, every time I rerun the function to add a new date, it adds the new date and value but it also overrides the previous date's value. What am I doing wrong?

Thanks!