Merge email package 4.0 from the sandbox, including documentation, test cases,
and NEWS updates.
diff --git a/Lib/email/errors.py b/Lib/email/errors.py
new file mode 100644
index 0000000..d52a624
--- /dev/null
+++ b/Lib/email/errors.py
@@ -0,0 +1,57 @@
+# Copyright (C) 2001-2006 Python Software Foundation
+# Author: Barry Warsaw
+# Contact: email-sig@python.org
+
+"""email package exception classes."""
+
+
+
+class MessageError(Exception):
+    """Base class for errors in the email package."""
+
+
+class MessageParseError(MessageError):
+    """Base class for message parsing errors."""
+
+
+class HeaderParseError(MessageParseError):
+    """Error while parsing headers."""
+
+
+class BoundaryError(MessageParseError):
+    """Couldn't find terminating boundary."""
+
+
+class MultipartConversionError(MessageError, TypeError):
+    """Conversion to a multipart is prohibited."""
+
+
+class CharsetError(MessageError):
+    """An illegal charset was given."""
+
+
+
+# These are parsing defects which the parser was able to work around.
+class MessageDefect:
+    """Base class for a message defect."""
+
+    def __init__(self, line=None):
+        self.line = line
+
+class NoBoundaryInMultipartDefect(MessageDefect):
+    """A message claimed to be a multipart but had no boundary parameter."""
+
+class StartBoundaryNotFoundDefect(MessageDefect):
+    """The claimed start boundary was never found."""
+
+class FirstHeaderLineIsContinuationDefect(MessageDefect):
+    """A message had a continuation line as its first header line."""
+
+class MisplacedEnvelopeHeaderDefect(MessageDefect):
+    """A 'Unix-from' header was found in the middle of a header block."""
+
+class MalformedHeaderDefect(MessageDefect):
+    """Found a header that was missing a colon, or was otherwise malformed."""
+
+class MultipartInvariantViolationDefect(MessageDefect):
+    """A message claimed to be a multipart but no subparts were found."""