code: def init_cli(self, app):
          
          # in case click isn't installed after all
          if click is None:
              raise RuntimeError('Cannot import click. Is it installed?')
          # only add commands if we have a click context available
          from .cli import add_commands
          add_commands(app.cli, self)
docs: Initialize the Flask CLI support in case it was enabled for the
          app.
  
          Works with both Flask>=1.0's CLI support as well as the backport
          in the Flask-CLI package for Flask<1.0.