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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 max_variants(composition):
 """Calculates the maximum number of isotopic variants that could be produced by a composition. Parameters composition : Mapping Any Mapping type where keys are element symbols and values are integers Returns ------- max_n_variants : int """

    max_n_variants = 0

    for element, count in composition.items():
        if element == "H+":
            continue
        try:
            max_n_variants += count * periodic_table[element].max_neutron_shift()
        except KeyError:
            pass

    return max_n_variants