Retrieve an entity from a single key (if it exists).

        .. note::

           This is just a thin wrapper over :meth:`get_multi`.
           The backend API does not make a distinction between a single key or
           multiple keys in a lookup request.

        :type key: :class:`google.cloud.datastore.key.Key`
        :param key: The key to be retrieved from the datastore.

        :type missing: list
        :param missing: (Optional) If a list is passed, the key-only entities
                        returned by the backend as "missing" will be copied
                        into it.

        :type deferred: list
        :param deferred: (Optional) If a list is passed, the keys returned
                         by the backend as "deferred" will be copied into it.

        :type transaction:
            :class:`~google.cloud.datastore.transaction.Transaction`
        :param transaction: (Optional) Transaction to use for read consistency.
                            If not passed, uses current transaction, if set.

        :type eventual: bool
        :param eventual: (Optional) Defaults to strongly consistent (False).
                         Setting True will use eventual consistency, but cannot
                         be used inside a transaction or will raise ValueError.

        :rtype: :class:`google.cloud.datastore.entity.Entity` or ``NoneType``
        :returns: The requested entity if it exists.

        :raises: :class:`ValueError` if eventual is True and in a transaction.

def get(self, key, missing=None, deferred=None, transaction=None, eventual=False):
        """Retrieve an entity from a single key (if it exists).

        .. note::

           This is just a thin wrapper over :meth:`get_multi`.
           The backend API does not make a distinction between a single key or
           multiple keys in a lookup request.

        :type key: :class:`google.cloud.datastore.key.Key`
        :param key: The key to be retrieved from the datastore.

        :type missing: list
        :param missing: (Optional) If a list is passed, the key-only entities
                        returned by the backend as "missing" will be copied
                        into it.

        :type deferred: list
        :param deferred: (Optional) If a list is passed, the keys returned
                         by the backend as "deferred" will be copied into it.

        :type transaction:
            :class:`~google.cloud.datastore.transaction.Transaction`
        :param transaction: (Optional) Transaction to use for read consistency.
                            If not passed, uses current transaction, if set.

        :type eventual: bool
        :param eventual: (Optional) Defaults to strongly consistent (False).
                         Setting True will use eventual consistency, but cannot
                         be used inside a transaction or will raise ValueError.

        :rtype: :class:`google.cloud.datastore.entity.Entity` or ``NoneType``
        :returns: The requested entity if it exists.

        :raises: :class:`ValueError` if eventual is True and in a transaction.
        """
        entities = self.get_multi(
            keys=[key],
            missing=missing,
            deferred=deferred,
            transaction=transaction,
            eventual=eventual,
        )
        if entities:
            return entities[0]