Checks in Python are pretty concise. If you just want to have a default value if the key my_value doesn't exist, this is all you need:

    value_I_want = some_dict.get('my_value', default_value)

If you want a more strict check including type checking:

    value_I_want = some_dict.get('my_value')
    if type(value_I_want) is not str:
        do_something()

In Java the real problem is nested JSON objects -- it's a real PITA to read those. You can't do something like this (Python):

    value = some_dict.get("foo", {}).get("bar", {}).get("blah", default_value)