why charge references act python inheritance?

the following seems strange.. basically, somedata charge seems common between classes hereditary the_base_class.

class the_base_class:
    somedata = {}
    somedata['was_false_in_base'] = false


class subclassthing(the_base_class):
    def __init__(self):
            imitation self.somedata


first = subclassthing()
{'was_false_in_base': false}
first.somedata['was_false_in_base'] = true
second = subclassthing()
{'was_false_in_base': true}
>>> del first
>>> del second
>>> third = subclassthing()
{'was_false_in_base': true}

defining self.somedata __init__ duty apparently repremand proceed around (so any category it's possess somedata dict) - nonetheless such function desirable?