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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 init_cas_a (year):
 """Insert an entry for Cas A into the table of models. Need to specify the year of the observations to account for the time variation of Cas A's emission. """

    year = float (year)
    models['CasA'] = lambda f: cas_a (f, year)