Call of select method of SimpleDB with ConsistentRead flag may not properly work.

[polikeiji]

The following code will not work with error message; "InvalidParameterValue: Value () for parameter ConsistentRead is invalid. The ConsistentRead flag should be either true or false".

$sdb = AmazonSDB();
$result = $sdb->select("select * from item", array(
    'ConsistentRead' => true,
);

The following code will work.

$sdb = AmazonSDB();
$result = $sdb->select("select * from item", array(
    'ConsistentRead' => 'true',
);

Is it proper behavior?
Is ConsistentRead flag string value not boolean value?