def CP(df1, df2, price1='Close', price2='Close'):
    """
    Comparative Performance
    Returns: list of floats = jhta.CP(df1, df2, price1='Close', price2='Close')
    Source: https://www.fmlabs.com/reference/default.htm?url=CompPerformance.htm
    """
    cp_list = []
    for i in range(len(df1[price1])):
        cp = 1 + (df1[price1][i] / df2[price2][i] - df1[price1][0] / df2[
            price2][0]) / (df1[price1][0] / df2[price2][0])
        cp_list.append(cp)
    return cp_list
