check if there is elements in list python code example

Example 1: Check if element in list Python

listA = [item1, item2, item3]
if item4 in listA:
  print('yes, item4 is in the list')
else:
  print('no, item4 is not in the list')

Example 2: python check if list contains value

if value in list:
  #do stuff

#Also to check if it doesn't contain
if value not in list:
  #do stuff