private function getOauthFields()
    {
        $this->oAuthFields = [
            'grant_type' => 'client_credentials',
            'scope' => $this->scope,
            'client_secret' => $this->mpClientSecret,
            'client_id' => $this->mpClientId,
        ];

        $this->fieldCount = count($this->oAuthFields);

        return $this->oAuthFields;
    }