python判断key是否存在

d = {1: 10, 2: 20, 3: 30, 4: 40, 5: 50, 6: 60}  
def is_key_present(x):  
  if x in d:  
      print('Key is present in the dictionary')  
  else:  
      print('Key is not present in the dictionary')  
is_key_present(5)  
is_key_present(9)