--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/planemo/lib/python3.7/site-packages/pip/_internal/utils/deprecation.py	Fri Jul 31 00:32:28 2020 -0400
@@ -0,0 +1,100 @@
+"""
+A module that implements tooling to enable easy warnings about deprecations.
+"""
+from __future__ import absolute_import
+
+import logging
+import warnings
+
+from pip._vendor.packaging.version import parse
+
+from pip import __version__ as current_version
+from pip._internal.utils.typing import MYPY_CHECK_RUNNING
+
+if MYPY_CHECK_RUNNING:
+    from typing import Any, Optional
+
+
+DEPRECATION_MSG_PREFIX = "DEPRECATION: "
+
+
+class PipDeprecationWarning(Warning):
+    pass
+
+
+_original_showwarning = None  # type: Any
+
+
+# Warnings <-> Logging Integration
+def _showwarning(message, category, filename, lineno, file=None, line=None):
+    if file is not None:
+        if _original_showwarning is not None:
+            _original_showwarning(
+                message, category, filename, lineno, file, line,
+            )
+    elif issubclass(category, PipDeprecationWarning):
+        # We use a specially named logger which will handle all of the
+        # deprecation messages for pip.
+        logger = logging.getLogger("pip._internal.deprecations")
+        logger.warning(message)
+    else:
+        _original_showwarning(
+            message, category, filename, lineno, file, line,
+        )
+
+
+def install_warning_logger():
+    # type: () -> None
+    # Enable our Deprecation Warnings
+    warnings.simplefilter("default", PipDeprecationWarning, append=True)
+
+    global _original_showwarning
+
+    if _original_showwarning is None:
+        _original_showwarning = warnings.showwarning
+        warnings.showwarning = _showwarning
+
+
+def deprecated(reason, replacement, gone_in, issue=None):
+    # type: (str, Optional[str], Optional[str], Optional[int]) -> None
+    """Helper to deprecate existing functionality.
+
+    reason:
+        Textual reason shown to the user about why this functionality has
+        been deprecated.
+    replacement:
+        Textual suggestion shown to the user about what alternative
+        functionality they can use.
+    gone_in:
+        The version of pip does this functionality should get removed in.
+        Raises errors if pip's current version is greater than or equal to
+        this.
+    issue:
+        Issue number on the tracker that would serve as a useful place for
+        users to find related discussion and provide feedback.
+
+    Always pass replacement, gone_in and issue as keyword arguments for clarity
+    at the call site.
+    """
+
+    # Construct a nice message.
+    #   This is eagerly formatted as we want it to get logged as if someone
+    #   typed this entire message out.
+    sentences = [
+        (reason, DEPRECATION_MSG_PREFIX + "{}"),
+        (gone_in, "pip {} will remove support for this functionality."),
+        (replacement, "A possible replacement is {}."),
+        (issue, (
+            "You can find discussion regarding this at "
+            "https://github.com/pypa/pip/issues/{}."
+        )),
+    ]
+    message = " ".join(
+        template.format(val) for val, template in sentences if val is not None
+    )
+
+    # Raise as an error if it has to be removed.
+    if gone_in is not None and parse(current_version) >= parse(gone_in):
+        raise PipDeprecationWarning(message)
+
+    warnings.warn(message, category=PipDeprecationWarning, stacklevel=2)