def repeat_range(pattern, nmin, nmax):
    """ `m` to `n` repeats of a pattern

    :param pattern: an `re` pattern
    :type pattern: str
    :param nmin: minimum number of repeats
    :type nmin: int
    :param nmax: maximum number of repeats
    :type nmax: int

    :rtype: str
    """
    return r'(?:{:s}){{{:d},{:d}}}'.format(pattern, nmin, nmax)