def findBinaryDataType(params):
    """ #TODO: docstring
    from: http://www.peptideatlas.org/tmp/mzML1.1.0.html#binaryDataArray
    a binaryDataArray "MUST supply a *child* term of MS:1000518
    (binary data type) only once"

    :param params: #TODO: docstring

    :returns: #TODO: docstring
    """
    binaryDataType = None
    cvParam = None
    for param in params:
        if param[0] in binaryDataArrayTypes:
            binaryDataType = binaryDataArrayTypes[param[0]]
            cvParam = param
            break
    return binaryDataType, cvParam