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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 _get(self, field):
 """ Return the value for the queried field. Get the value of a given field. The list of all queryable fields is documented in the beginning of the model class. Parameters field : string Name of the field to be retrieved. Returns ------- out : value The current value of the requested field. """

        if field in self._list_fields():
            return self.__proxy__.get(field)
        else:
            raise KeyError('Key \"%s\" not in model. Available fields are %s.' % (field, ', '.join(self._list_fields())))