def get_dimpositions(dimstring, tocheck=['B', 'S', 'T', 'Z', 'C']):
    """Simple function to get the indices of the dimension identifiers in a string

    :param dimstring: dimension string
    :type dimstring: str
    :param tocheck: list of entries to check, defaults to ['B', 'S', 'T', 'Z', 'C']
    :type tocheck: list, optional
    :return: dictionary with positions of dimensions inside string
    :rtype: dict
    """
    dimpos = {}
    for p in tocheck:
        dimpos[p] = dimstring.find(p)

    return dimpos