d = {'a': "Valor de A", 'b': "Valor de B"}
if 'a' in d:
print("Dicionário possui a chave 'a'")
if 'b' in d:
print("Dicionário possui a chave 'b'")
if 'c' in d:
print("Dicionário possui a chave 'c'")
ZCA9IHsnYSc6ICJWYWxvciBkZSBBIiwgJ2InOiAiVmFsb3IgZGUgQiJ9CgppZiAnYScgaW4gZDoKICAgIHByaW50KCJEaWNpb27DoXJpbyBwb3NzdWkgYSBjaGF2ZSAnYSciKQoKaWYgJ2InIGluIGQ6CiAgICBwcmludCgiRGljaW9uw6FyaW8gcG9zc3VpIGEgY2hhdmUgJ2InIikKCmlmICdjJyBpbiBkOgogICAgcHJpbnQoIkRpY2lvbsOhcmlvIHBvc3N1aSBhIGNoYXZlICdjJyIp