def _get_transposition(e):
    """
    Get the transposition of the respective part. This is used for
    instruments that are notated in transposed fashion. Pitches will have
    to be transposed by the given amount to be in "correct" concert pitch
    (and thus in tune with the other instruments).

    Returns
    -------

    (diat, chrom) : tuple of int
        the amount of steps (+/-) that the pitches have to be adjusted.
        `diat` means steps in diatonic scale (could be min 2nd or maj 2nd?),
        `chrom` means steps in chromatic scale, thus half steps (min 2nd)
    """

    diat = None
    chrom = None

    if e.find('transpose/diatonic') is not None:
        diat = int(e.find('transpose/diatonic').text)
    if e.find('transpose/chromatic') is not None:
        chrom = int(e.find('transpose/chromatic').text)
    if diat is None and chrom is None:
        return None
    else:
        return (diat, chrom)