def find_plugins(self, plugin_env, full_env=None, installer=None,<EOL>fallback=True):
plugin_projects = list(plugin_env)<EOL>plugin_projects.sort()<EOL>error_info = {}<EOL>distributions = {}<EOL>if full_env is None:<EOL><INDENT>env = Environment(self.entries)<EOL>env += plugin_env<EOL><DEDENT>else:<EOL><INDENT>env = full_env + plugin_env<EOL><DEDENT>shadow_set = self.__class__([])<EOL>list(map(shadow_set.add, self))<EOL>for project_name in plugin_projects:<EOL><INDENT>for dist in plugin_env[project_name]:<EOL><INDENT>req = [dist.as_requirement()]<EOL>try:<EOL><INDENT>resolvees = shadow_set.resolve(req, env, installer)<EOL><DEDENT>except ResolutionError:<EOL><INDENT>v = sys.exc_info()[<NUM_LIT:1>]<EOL>error_info[dist] = v<EOL>if fallback:<EOL><INDENT>continue<EOL><DEDENT>else:<EOL><INDENT>break<EOL><DEDENT><DEDENT>else:<EOL><INDENT>list(map(shadow_set.add, resolvees))<EOL>distributions.update(dict.fromkeys(resolvees))<EOL>break<EOL><DEDENT><DEDENT><DEDENT>distributions = list(distributions)<EOL>distributions.sort()<EOL>return distributions, error_info<EOL>
Find all activatable distributions in `plugin_env`

        Example usage::

            distributions, errors = working_set.find_plugins(
                Environment(plugin_dirlist)
            )
            # add plugins+libs to sys.path
            map(working_set.add, distributions)
            # display errors
            print('Could not load', errors)

        The `plugin_env` should be an ``Environment`` instance that contains
        only distributions that are in the project's "plugin directory" or
        directories. The `full_env`, if supplied, should be an ``Environment``
        contains all currently-available distributions.  If `full_env` is not
        supplied, one is created automatically from the ``WorkingSet`` this
        method is called on, which will typically mean that every directory on
        ``sys.path`` will be scanned for distributions.

        `installer` is a standard installer callback as used by the
        ``resolve()`` method. The `fallback` flag indicates whether we should
        attempt to resolve older versions of a plugin if the newest version
        cannot be resolved.

        This method returns a 2-tuple: (`distributions`, `error_info`), where
        `distributions` is a list of the distributions found in `plugin_env`
        that were loadable, along with any other distributions that are needed
        to resolve their dependencies.  `error_info` is a dictionary mapping
        unloadable plugin distributions to an exception instance describing the
        error that occurred. Usually this will be a ``DistributionNotFound`` or
        ``VersionConflict`` instance.