--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/planemo/lib/python3.7/site-packages/virtualenv/config/env_var.py	Fri Jul 31 00:32:28 2020 -0400
@@ -0,0 +1,29 @@
+from __future__ import absolute_import, unicode_literals
+
+import os
+
+from virtualenv.util.six import ensure_str, ensure_text
+
+from .convert import convert
+
+
+def get_env_var(key, as_type):
+    """Get the environment variable option.
+
+    :param key: the config key requested
+    :param as_type: the type we would like to convert it to
+    :return:
+    """
+    environ_key = ensure_str("VIRTUALENV_{}".format(key.upper()))
+    if os.environ.get(environ_key):
+        value = os.environ[environ_key]
+        # noinspection PyBroadException
+        try:
+            source = "env var {}".format(ensure_text(environ_key))
+            as_type = convert(value, as_type, source)
+            return as_type, source
+        except Exception:  # note the converter already logs a warning when failures happen
+            pass
+
+
+__all__ = ("get_env_var",)