Checking number in a list to see if they are beside each other

[Allaye]

List1 =[2,3,4,9,9,5,1]
def checkList(List1):
    for i in range(len(List1 - 1)):
      
if List1[i] == 9 and List1[i+1] == 9:
            return True
          return false 

i want to check if the number 9 comes b4 any other number in the list but my problem is the code does not return true or false