src/Isbn.php
public function getGroupName() : string
    {
        if ($this->rangeInfo === null) {
            throw IsbnException::unknownGroup($this->isbn);
        }

        return $this->rangeInfo->groupName;
    }
public function getGroupName() : string
    {
        if ($this->rangeInfo === null) {
            throw IsbnException::unknownGroup($this->isbn);
        }

        return $this->rangeInfo->groupName;
    }
public function getGroupName ( ) : string { if ( $ this -> rangeInfo === null ) { throw IsbnException :: unknownGroup ( $ this -> isbn ) ; } return $ this -> rangeInfo -> groupName ; }
Returns the group name.

@return string

@throws IsbnException If this ISBN is not in a recognized group.
Returns the group name .