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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def apply_plugins(plugin_names):
 """ This function should be used by code in the SQUAD core to trigger functionality from plugins. The ``plugin_names`` argument is list of plugins names to be used. Most probably, you will want to pass the list of plugins enabled for a given project, e.g. ``project.enabled_plugins``. Example:: from squad.core.plugins import apply_plugins for plugin in apply_plugins(project.enabled_plugins):
 """

    if plugin_names is None:
        return

    for p in plugin_names:
        try:
            plugin = get_plugin_instance(p)
            yield(plugin)
        except PluginNotFound:
            pass