Example Of Update_item In Dynamodb Boto3

Following the documentation, I'm trying to create an update statement that will update or add if not exists only one attribute in a dynamodb table.

I'm trying this

response = table.update_item(
    Key={'ReleaseNumber': '1.0.179'},
    UpdateExpression='SET',
    ConditionExpression='Attr(\'ReleaseNumber\').eq(\'1.0.179\')',
    ExpressionAttributeNames={'attr1': 'val1'},
    ExpressionAttributeValues={'val1': 'false'}
)

The error I'm getting is:

botocore.exceptions.ClientError: An error occurred (ValidationException) when calling the UpdateItem operation: ExpressionAttributeNames contains invalid key: Syntax error; key: "attr1"

If anyone has done anything similar to what I'm trying to achieve please share example.

Found working example here, very important to list as Keys all the indexes of the table, this will require additional query before update, but it works.

response = table.update_item(
    Key={
        'ReleaseNumber': releaseNumber,
        'Timestamp': result[0]['Timestamp']
    },
    UpdateExpression="set Sanity = :r",
    ExpressionAttributeValues={
        ':r': 'false',
    },
    ReturnValues="UPDATED_NEW"
)