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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 to_cloudformation(self, **kwargs):
 """Returns the Lambda Permission resource allowing S3 to invoke the function this event source triggers. :param dict kwargs: S3 bucket resource :returns: a list of vanilla CloudFormation Resources, to which this S3 event expands :rtype: list """

        function = kwargs.get('function')

        if not function:
            raise TypeError("Missing required keyword argument: function")

        if 'bucket' not in kwargs or kwargs['bucket'] is None:
            raise TypeError("Missing required keyword argument: bucket")

        if 'bucket_id' not in kwargs or kwargs['bucket_id'] is None:
            raise TypeError("Missing required keyword argument: bucket_id")

        bucket = kwargs['bucket']
        bucket_id = kwargs['bucket_id']

        resources = []

        source_account = ref('AWS::AccountId')
        permission = self._construct_permission(function, source_account=source_account)
        if CONDITION in permission.resource_attributes:
            self._depend_on_lambda_permissions_using_tag(bucket, permission)
        else:
            self._depend_on_lambda_permissions(bucket, permission)
        resources.append(permission)

        # NOTE: `bucket` here is a dictionary representing the S3 Bucket resource in your SAM template. If there are
        # multiple S3 Events attached to the same bucket, we will update the Bucket resource with notification
        # configuration for each event. This is the reason why we continue to use existing bucket dict and append onto
        # it.
        #
        # NOTE: There is some fragile logic here where we will append multiple resources to output
        #   SAM template but de-dupe them when merging into output CFN template. This is scary because the order of
        #   merging is literally "last one wins", which works fine because we linearly loop through the template once.
        #   The de-dupe happens inside `samtranslator.translator.Translator.translate` method when merging results of
        #   to_cloudformation() to output template.
        self._inject_notification_configuration(function, bucket)
        resources.append(S3Bucket.from_dict(bucket_id, bucket))

        return resources