Write $2$ unit tests for the $3$ functions below $($add$\_$by$\_$kind, add$\_$by$\_$date and lookup$\_$by$\_$kind$\_$and$\_$date$).$ Remember that a unit test function name starts with test$\_.$

The $2$ unit tests should consist of:

$-$One edge case

$-$One use case

Include descriptive function names and docstrings, so that it captures what is being tested.

def add$\_$by$\_$kind$($garden$\_$dict, kind, plant$)$:

if kind in garden$\_$dict:

garden$\_$dict$[$kind$].$append$($plant$)$

else:

garden$\_$dict$[$kind$]=[$plant$]$

def add$\_$by$\_$date$($garden$\_$dict, date, plant$)$:

if date in garden$\_$dict:

garden$\_$dict$[$date$].$append$($plant$)$

else:

garden$\_$dict$[$date$]=[$plant$]$

def lookup$\_$by$\_$kind$\_$and$\_$date$($kind$\_$dict, date$\_$dict, kind, date$)$:

plants$\_$to$\_$plant $=[]$

if kind in kind$\_$dict and date in date$\_$dict:

for plant in kind$\_$dict$[$kind$]$:

if plant in date$\_$dict$[$date$]$:

plants$\_$to$\_$plant.append$($plant$)$

return plants$\_$to$\_$plant