check if something exists in a 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: how to check if value is in list python

>>> letters = [a,b,c,d,e]
>>> 'a' in letters:
True