I have a dictionary that looks like this:

```
directions = {"north": ["n", "N", "north", "North"],
              "south": ["s", "S", "south", "South"],
              "east": ["e", "E", "east", "East"],
              "west": ["w", "W", "west", "West"]}

```

I want to:
1) check if a variable (direction) exists at all in any of the lists in the dictionary
2) get the dictionary key of the list the value is in. How could this be done?