I wasn't able to find out how to do this elsewhere, but it is probably simple. I'm trying to capitalise the `value` associated with the dict `strings`, but am currently only able to apitalise the actual `key` itself. 

```
strings = {"1234":{'a'}, "2":{'as'}, "4":{'bat'}, "5":{'car'}, "6":{'dove'}, "7":{'python'}}

```

I know this is not right:

```
d = {key:key.upper() for key in strings}

```

This resulted in an error, because I was trying to unpack too many variables:

```
d = {key:value.upper() for (key,value) in strings}

```