The Request $accept property is a Sapien\Request\Header\Accept object.
The Accept object has these readonly ValueCollection properties:
TypeCollection $types: A collection of Accept\Type objects computed from
$header['accept'].
CharsetCollection $charsets: A collection of Accept\Charset objects computed from
$header['accept-charset'].
EncodingCollection $encodings: A collection of Accept\Encoding objects computed from
$header['accept-encoding'].
LanguageCollection $languages: A collection of Accept\Language objects computed from
$header['accept-language'].
Each collection is sorted from highest q parameter value to lowest.
Each Accept\* object has these readonly properties:
string $value: The main value of the accept header.
string $quality: The 'q=' parameter value.
array $params: A key-value array of all other parameters.
Each Accept\Language object has these additional readonly properties:
string $type: The language type.
?string $subtype: The language subtype, if any.