calling a function which takes a dictionary as argument

[Mekire]

Also note, as your function is altering the dictionary in place there is no need for the return statements.

You could just write this:

dic = {3:0.2, 4:0.5, 5:0.1, 6:0.8, 7:0.34}
  
def function(dic):
   if dic:
      dic[100] = 0.1
  
function(dic)
print(dic[100])