old_contents: from .deployer import PackageDeployer
  from .providers import CachingPackageProvider
  from .sources import PackageSourceFetcher
  
  
  class Installer(object):
      def __init__(self, package_provider, package_source_repo_uris=None):
          if package_source_repo_uris is None:
              package_source_repo_uris = []
              
          self._package_provider = package_provider
          self._package_source_fetcher = PackageSourceFetcher(package_source_repo_uris)
          self._deployer = PackageDeployer()
  
      def install(self, package_name, install_dir, params=None):
          with self._fetch_package_source(package_name) as package_source:
              return self.install_from_package_source(package_source, install_dir, params)
              
      def install_from_package_source(self, package_source, install_dir, params=None):
          if params is None:
              params = {}
              
          with self._provide_package(package_source, params) as package_dir:
              self._deployer.deploy(package_source, package_dir, install_dir)
              
      def _provide_package(self, package_source, params):
          return self._package_provider.provide_package(package_source, params)
              
      def _fetch_package_source(self, package_name):
          return self._package_source_fetcher.fetch(package_name)
  
new_contents: from .deployer import PackageDeployer
  from .sources import PackageSourceFetcher
  
  
  class Installer(object):
      def __init__(self, package_provider, package_source_repo_uris=None):
          if package_source_repo_uris is None:
              package_source_repo_uris = []
              
          self._package_provider = package_provider
          self._package_source_fetcher = PackageSourceFetcher(package_source_repo_uris)
          self._deployer = PackageDeployer()
  
      def install(self, package_name, install_dir, params=None):
          with self._fetch_package_source(package_name) as package_source:
              return self.install_from_package_source(package_source, install_dir, params)
              
      def install_from_package_source(self, package_source, install_dir, params=None):
          if params is None:
              params = {}
              
          with self._provide_package(package_source, params) as package_dir:
              self._deployer.deploy(package_source, package_dir, install_dir)
              
      def _provide_package(self, package_source, params):
          return self._package_provider.provide_package(package_source, params)
              
      def _fetch_package_source(self, package_name):
          return self._package_source_fetcher.fetch(package_name)
  
subject: Remove unused import