def __init__(self, key, primer):
        """Initialize the _Processor instance if it is from a child class.

        After passing several tests for creating a valid processing object,
        the key is saved, and the primer is used to start an index. Tables
        are also formed for converting byte values between systems."""
        if self.__class__ is _Processor:
            raise NotImplementedError('This is an abstract class!')
        key.test_primer(primer)
        self.__key = key
        self.__into = table = dict(map(reversed, enumerate(key.order)))
        self.__index = deque(map(table.__getitem__, primer.data),
                             key.dimensions)
        self.__from = dict(map(reversed, table.items()))
Initialize the _Processor instance if it is from a child class.

        After passing several tests for creating a valid processing object,
        the key is saved, and the primer is used to start an index. Tables
        are also formed for converting byte values between systems.
recipes/Python/578075_Markov_Encryption_Module/recipe-578075.py