<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def add_package(self, package):
 """ Add a package to this project """

        self._data.setdefault('packages', {})
        
        self._data['packages'][package.name] = package.source

        for package in package.deploy_packages:
            self.add_package(package)

        self._save()