def camel_case(st, upper=False):
    """
    Convert string to camel-case (upper or lower)

    :param st: input string
    :type st: ```str```

    :param upper: upper camelcase if True, else lower camelcase
    :type upper: ```bool```

    :return: camel case representation of input string
    :rtype: ```str```
    """
    output = "".join(x for x in st.title() if x.isalnum())
    return getattr(output[0], "upper" if upper else "lower")() + output[1:]