--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/planemo/lib/python3.7/site-packages/packaging/utils.py	Fri Jul 31 00:32:28 2020 -0400
@@ -0,0 +1,65 @@
+# This file is dual licensed under the terms of the Apache License, Version
+# 2.0, and the BSD License. See the LICENSE file in the root of this repository
+# for complete details.
+from __future__ import absolute_import, division, print_function
+
+import re
+
+from ._typing import TYPE_CHECKING, cast
+from .version import InvalidVersion, Version
+
+if TYPE_CHECKING:  # pragma: no cover
+    from typing import NewType, Union
+
+    NormalizedName = NewType("NormalizedName", str)
+
+_canonicalize_regex = re.compile(r"[-_.]+")
+
+
+def canonicalize_name(name):
+    # type: (str) -> NormalizedName
+    # This is taken from PEP 503.
+    value = _canonicalize_regex.sub("-", name).lower()
+    return cast("NormalizedName", value)
+
+
+def canonicalize_version(_version):
+    # type: (str) -> Union[Version, str]
+    """
+    This is very similar to Version.__str__, but has one subtle difference
+    with the way it handles the release segment.
+    """
+
+    try:
+        version = Version(_version)
+    except InvalidVersion:
+        # Legacy versions cannot be normalized
+        return _version
+
+    parts = []
+
+    # Epoch
+    if version.epoch != 0:
+        parts.append("{0}!".format(version.epoch))
+
+    # Release segment
+    # NB: This strips trailing '.0's to normalize
+    parts.append(re.sub(r"(\.0)+$", "", ".".join(str(x) for x in version.release)))
+
+    # Pre-release
+    if version.pre is not None:
+        parts.append("".join(str(x) for x in version.pre))
+
+    # Post-release
+    if version.post is not None:
+        parts.append(".post{0}".format(version.post))
+
+    # Development release
+    if version.dev is not None:
+        parts.append(".dev{0}".format(version.dev))
+
+    # Local version segment
+    if version.local is not None:
+        parts.append("+{0}".format(version.local))
+
+    return "".join(parts)