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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:

def union(lst1, lst2):
    '''
    Returns the union of two lists.

    .. code-block:: jinja

        {% my_list = [1,2,3,4] -%}
        {{ set my_list | union([2, 4, 6]) }}

    will be rendered as:

    .. code-block:: text

        [1, 2, 3, 4, 6]
    '''
    if isinstance(lst1, collections.Hashable) and isinstance(lst2, collections.Hashable):
        return set(lst1) | set(lst2)
    return unique(lst1 + lst2)