user: ###Story
Sometimes we are faced with problems when we have a big nested dictionary with which it's hard to work. Now, we need to solve this problem by writing a function that will flatten a given dictionary.

###Info
Python dictionaries are a convenient data type to store and process configurations. They allow you to store data by keys to create nested structures. You are given a dictionary where the keys are strings and the values are strings or dictionaries. The goal is flatten the dictionary, but save the structures in the keys. The result should be a dictionary without the nested dictionaries. The keys should contain paths that contain the parent keys from the original dictionary. The keys in the path are separated by a `/`. If a value is an empty dictionary, then it should be replaced by an empty string `""`.

###Examples
```python
{
    "name": {
        "first": "One",
        "last": "Drone"
    },
    "job": "scout",
    "recent": {},
    "additional": {
        "place": {
            "zone": "1",
            "cell": "2"
        }
    }
}
```
The result will be:
```python
{"name/first": "One",           #one parent
 "name/last": "Drone",
 "job": "scout",                #root key
 "recent": "",                  #empty dict
 "additional/place/zone": "1",  #third level
 "additional/place/cell": "2"}
```

***`Input: An original dictionary as a dict.`***
***`Output: The flattened dictionary as a dict.`***
***`Precondition:
Keys in a dictionary are non-empty strings.
Values in a dictionary are strings or dicts.
root_dictionary != {}`***

```python
flatten({"key": "value"}) == {"key": "value"}
flatten({"key": {"deeper": {"more": {"enough": "value"}}}}) == {"key/deeper/more/enough": "value"}
flatten({"empty": {}}) == {"empty": ""}
```

Answer: {"fn_name": "flatten", "inputs": [[{"key": "value"}], [{"key": {"deeper": {"more": {"enough": "value"}}}}], [{"empty": {}}], [{"additional": {"place": {"cell": "2", "zone": "1"}}, "job": "scout", "name": {"last": "Drone", "first": "One"}, "recent": {}}], [{"job": {"1": "scout", "2": "worker", "3": "writer", "4": "reader", "5": "learner"}, "name": {"nick": {}, "last": "Drone", "first": "Second"}, "recent": {"places": {"earth": {"NP": "", "NY": "2017", "Louvre": "2015"}}, "times": {"XX": {"1964": "Yes"}, "XXI": {"2064": "Nope"}}}}], [{"Hm": {"What": {"is": {"here": {"?": {}}}}}}], [{"glossary": {"GlossDiv": {"GlossList": {"GlossEntry": {"GlossDef": {"GlossSeeAlso": {"1": "GML", "2": "XML"}, "para": "A meta-markup language, used to create markup languages such as DocBook."}, "GlossSee": "markup", "Acronym": "SGML", "GlossTerm": "Standard Generalized Markup Language", "Abbrev": "ISO 8879:1986", "SortAs": "SGML", "ID": "SGML"}}, "title": "S"}, "title": "example glossary"}, "source": "http://json.org/example"}]], "outputs": [[{"key": "value"}], [{"key/deeper/more/enough": "value"}], [{"empty": ""}], [{"additional/place/zone": "1", "job": "scout", "additional/place/cell": "2", "name/first": "One", "name/last": "Drone", "recent": ""}], [{"job/1": "scout", "recent/places/earth/NY": "2017", "job/3": "writer", "job/2": "worker", "job/5": "learner", "job/4": "reader", "recent/places/earth/NP": "", "recent/places/earth/Louvre": "2015", "recent/times/XX/1964": "Yes", "recent/times/XXI/2064": "Nope", "name/first": "Second", "name/last": "Drone", "name/nick": ""}], [{"Hm/What/is/here/?": ""}], [{"glossary/GlossDiv/GlossList/GlossEntry/GlossDef/para": "A meta-markup language, used to create markup languages such as DocBook.", "glossary/title": "example glossary", "glossary/GlossDiv/GlossList/GlossEntry/Abbrev": "ISO 8879:1986", "glossary/GlossDiv/GlossList/GlossEntry/SortAs": "SGML", "glossary/GlossDiv/GlossList/GlossEntry/Acronym": "SGML", "glossary/GlossDiv/GlossList/GlossEntry/GlossTerm": "Standard Generalized Markup Language", "glossary/GlossDiv/title": "S", "source": "http://json.org/example", "glossary/GlossDiv/GlossList/GlossEntry/GlossDef/GlossSeeAlso/2": "XML", "glossary/GlossDiv/GlossList/GlossEntry/ID": "SGML", "glossary/GlossDiv/GlossList/GlossEntry/GlossDef/GlossSeeAlso/1": "GML", "glossary/GlossDiv/GlossList/GlossEntry/GlossSee": "markup"}]]}