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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 as_plural(result_key):
 """ Given a result key, return in the plural form. """

    # Not at all guaranteed to work in all cases...
    if result_key.endswith('y'):
        return re.sub("y$", "ies", result_key)
    elif result_key.endswith('address'):
        return result_key + 'es'
    elif result_key.endswith('us'):
        return re.sub("us$", "uses", result_key)
    elif not result_key.endswith('s'):
        return result_key + 's'
    else:
        return result_key