def unique_strategies(strategies):
    """
    Extract unique strategies from array of strategies.

    Parameters
    ----------
    strategies : Strategy list
        Strategies to be processed.

    Returns
    -------
    Strategy set :
        Unique strategies.
    """

    # Using set (we must define hash to use this)
    unique = list(set(strategies))

    # Using list
    #  unique = []
    #  # traverse for all elements
    #  for x in strategies:
    #      # check if x exists in unique_list or not
    #      if x not in unique:
    #          unique.append(x)

    return unique