--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/planemo/lib/python3.7/site-packages/virtualenv/run/plugin/base.py	Fri Jul 31 00:32:28 2020 -0400
@@ -0,0 +1,58 @@
+from __future__ import absolute_import, unicode_literals
+
+import sys
+from collections import OrderedDict
+
+if sys.version_info >= (3, 8):
+    from importlib.metadata import entry_points
+else:
+    from importlib_metadata import entry_points
+
+
+class PluginLoader(object):
+    _OPTIONS = None
+    _ENTRY_POINTS = None
+
+    @classmethod
+    def entry_points_for(cls, key):
+        return OrderedDict((e.name, e.load()) for e in cls.entry_points().get(key, {}))
+
+    @staticmethod
+    def entry_points():
+        if PluginLoader._ENTRY_POINTS is None:
+            PluginLoader._ENTRY_POINTS = entry_points()
+        return PluginLoader._ENTRY_POINTS
+
+
+class ComponentBuilder(PluginLoader):
+    def __init__(self, interpreter, parser, name, possible):
+        self.interpreter = interpreter
+        self.name = name
+        self._impl_class = None
+        self.possible = possible
+        self.parser = parser.add_argument_group(title=name)
+        self.add_selector_arg_parse(name, list(self.possible))
+
+    @classmethod
+    def options(cls, key):
+        if cls._OPTIONS is None:
+            cls._OPTIONS = cls.entry_points_for(key)
+        return cls._OPTIONS
+
+    def add_selector_arg_parse(self, name, choices):
+        raise NotImplementedError
+
+    def handle_selected_arg_parse(self, options):
+        selected = getattr(options, self.name)
+        if selected not in self.possible:
+            raise RuntimeError("No implementation for {}".format(self.interpreter))
+        self._impl_class = self.possible[selected]
+        self.populate_selected_argparse(selected, options.app_data)
+        return selected
+
+    def populate_selected_argparse(self, selected, app_data):
+        self.parser.description = "options for {} {}".format(self.name, selected)
+        self._impl_class.add_parser_arguments(self.parser, self.interpreter, app_data)
+
+    def create(self, options):
+        return self._impl_class(options, self.interpreter)