code: def _default_ctx(self):
          
          if not self.in_app_directory:
              print("Warning: {} does not exist. Using the default.".format(
                  self.package))
              ctx = {}
  
          else:
              with open(self.package) as f:
                  ctx = dict(yaml.load(f, Loader=yaml.RoundTripLoader))
  
          if self.in_app_directory:
              # Update the env for each platform
              excluded = list(ctx.get('excluded', []))
  
              for env in [ctx['ios'], ctx['android']]:
                  if 'python_build_dir' not in env:
                      env['python_build_dir'] = expanduser(abspath('build/python'))
                  if 'conda_prefix' not in env:
                      env['conda_prefix'] = os.environ.get(
                          'CONDA_PREFIX', expanduser(abspath('venv')))
  
                  # Join the shared and local exclusions
                  env['excluded'] = list(env.get('excluded', [])) + excluded
  
          return ctx
docs: Return the package config or context and normalize some of the 
          values