def append(self, other, ignore_index=False):
        """Append rows of `other` to the end of this frame, returning a new object.

        Wrapper around the :meth:`pandas.DataFrame.append` method.

        Args:
            other (Cartesian):
            ignore_index (sequence, bool, int): If it is a boolean, it
                behaves like in the description of
                :meth:`pandas.DataFrame.append`.
                If it is a sequence, it becomes the new index.
                If it is an integer,
                ``range(ignore_index, ignore_index + len(new))``
                becomes the new index.

        Returns:
            Cartesian:
        """
        if not isinstance(other, self.__class__):
            raise ValueError('May only append instances of same type.')
        if type(ignore_index) is bool:
            new_frame = self._frame.append(other._frame,
                                           ignore_index=ignore_index,
                                           verify_integrity=True)
        else:
            new_frame = self._frame.append(other._frame,
                                           ignore_index=True,
                                           verify_integrity=True)
            if type(ignore_index) is int:
                new_frame.index = range(ignore_index,
                                        ignore_index + len(new_frame))
            else:
                new_frame.index = ignore_index
        return self.__class__(new_frame)
Append rows of `other` to the end of this frame, returning a new object.

        Wrapper around the :meth:`pandas.DataFrame.append` method.

        Args:
            other (Cartesian):
            ignore_index (sequence, bool, int): If it is a boolean, it
                behaves like in the description of
                :meth:`pandas.DataFrame.append`.
                If it is a sequence, it becomes the new index.
                If it is an integer,
                ``range(ignore_index, ignore_index + len(new))``
                becomes the new index.

        Returns:
            Cartesian: