Given a list:

`lst = ['apple', 'orange', 'pears', 'pears', 'banana']`

and a dictionary

`dict = {'orange': 4, 'apple':2, 'pears': 1}`

if a string from the list already exist in dict update the value else add a new key and its counting.

result:

`dict = {'orange' = 5, 'apple':3, 'pears':3, 'banana':1}`

I tried:

```
count = 0
for string on lst:
    if string in dict.keys():
        for num in dict:
            count = count + num
            num = count

```

I don't know how to continue