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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 check(self, topic, value):
 """ Checking the value if it fits into the given specification """

        datatype_key = topic.meta.get('datatype', 'none')
        self._datatypes[datatype_key].check(topic, value)
        validate_dt = topic.meta.get('validate', None)
        if validate_dt:
            self._datatypes[validate_dt].check(topic, value)