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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_item(self, table_name, key_dict, consistent_read=False, expression_attribute_names=None, projection_expression=None, return_consumed_capacity=None):
 """ Invoke the `GetItem`_ function. :param str table_name: table to retrieve the item from :param dict key_dict: key to use for retrieval. This will be marshalled for you so a native :class:`dict` works. :param bool consistent_read: Determines the read consistency model: If set to :py:data`True`, then the operation uses strongly consistent reads; otherwise, the operation uses eventually consistent reads. :param dict expression_attribute_names: One or more substitution tokens for attribute names in an expression. :param str projection_expression: A string that identifies one or more attributes to retrieve from the table. These attributes can include scalars, sets, or elements of a JSON document. The attributes in the expression must be separated by commas. If no attribute names are specified, then all attributes will be returned. If any of the requested attributes are not found, they will not appear in the result. :param str return_consumed_capacity: Determines the level of detail about provisioned throughput consumption that is returned in the response: - INDEXES: The response includes the aggregate consumed capacity for the operation, together with consumed capacity for each table and secondary index that was accessed. Note that some operations, such as *GetItem* and *BatchGetItem*, do not access any indexes at all. In these cases, specifying INDEXES will only return consumed capacity information for table(s). - TOTAL: The response includes only the aggregate consumed capacity for the operation. - NONE: No consumed capacity details are included in the response. :rtype: tornado.concurrent.Future .. _GetItem: http://docs.aws.amazon.com/amazondynamodb/ latest/APIReference/API_GetItem.html """

        payload = {'TableName': table_name,
                   'Key': utils.marshall(key_dict),
                   'ConsistentRead': consistent_read}
        if expression_attribute_names:
            payload['ExpressionAttributeNames'] = expression_attribute_names
        if projection_expression:
            payload['ProjectionExpression'] = projection_expression
        if return_consumed_capacity:
            _validate_return_consumed_capacity(return_consumed_capacity)
            payload['ReturnConsumedCapacity'] = return_consumed_capacity
        return self.execute('GetItem', payload)