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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def _execute_inner(self, audio_file_mfcc, text_file, sync_root=None, force_aba_auto=False, log=True, leaf_level=False):
 """ Align a subinterval of the given AudioFileMFCC with the given TextFile. Return the computed tree of time intervals, rooted at ``sync_root`` if the latter is not ``None``, or as a new ``Tree`` otherwise. The begin and end positions inside the AudioFileMFCC must have been set ahead by the caller. The text fragments being aligned are the vchildren of ``text_file``. :param audio_file_mfcc: the audio file MFCC representation :type audio_file_mfcc: :class:`~aeneas.audiofilemfcc.AudioFileMFCC` :param text_file: the text file subtree to align :type text_file: :class:`~aeneas.textfile.TextFile` :param sync_root: the tree node to which fragments should be appended :type sync_root: :class:`~aeneas.tree.Tree` :param bool force_aba_auto: if ``True``, do not run aba algorithm :param bool log: if ``True``, log steps :param bool leaf_level: alert aba if the computation is at a leaf level :rtype: :class:`~aeneas.tree.Tree` """

        self._step_begin(u"synthesize text", log=log)
        synt_handler, synt_path, synt_anchors, synt_format = self._synthesize(text_file)
        self._step_end(log=log)

        self._step_begin(u"extract MFCC synt wave", log=log)
        synt_wave_mfcc = self._extract_mfcc(
            file_path=synt_path,
            file_format=synt_format,
        )
        gf.delete_file(synt_handler, synt_path)
        self._step_end(log=log)

        self._step_begin(u"align waves", log=log)
        indices = self._align_waves(audio_file_mfcc, synt_wave_mfcc, synt_anchors)
        self._step_end(log=log)

        self._step_begin(u"adjust boundaries", log=log)
        self._adjust_boundaries(indices, text_file, audio_file_mfcc, sync_root, force_aba_auto, leaf_level)
        self._step_end(log=log)