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diff --git a/third_party/dnspython/dns/rdataclass.py b/third_party/dnspython/dns/rdataclass.py
new file mode 100644
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+++ b/third_party/dnspython/dns/rdataclass.py
@@ -0,0 +1,114 @@
+# Copyright (C) 2001-2007, 2009-2011 Nominum, Inc.
+#
+# Permission to use, copy, modify, and distribute this software and its
+# documentation for any purpose with or without fee is hereby granted,
+# provided that the above copyright notice and this permission notice
+# appear in all copies.
+#
+# THE SOFTWARE IS PROVIDED "AS IS" AND NOMINUM DISCLAIMS ALL WARRANTIES
+# WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+# MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL NOMINUM BE LIABLE FOR
+# ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+# WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+# ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
+# OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+
+"""DNS Rdata Classes.
+
+@var _by_text: The rdata class textual name to value mapping
+@type _by_text: dict
+@var _by_value: The rdata class value to textual name mapping
+@type _by_value: dict
+@var _metaclasses: If an rdataclass is a metaclass, there will be a mapping
+whose key is the rdatatype value and whose value is True in this dictionary.
+@type _metaclasses: dict"""
+
+import re
+
+import dns.exception
+
+RESERVED0 = 0
+IN = 1
+CH = 3
+HS = 4
+NONE = 254
+ANY = 255
+
+_by_text = {
+    'RESERVED0' : RESERVED0,
+    'IN' : IN,
+    'CH' : CH,
+    'HS' : HS,
+    'NONE' : NONE,
+    'ANY' : ANY
+    }
+
+# We construct the inverse mapping programmatically to ensure that we
+# cannot make any mistakes (e.g. omissions, cut-and-paste errors) that
+# would cause the mapping not to be true inverse.
+
+_by_value = dict([(y, x) for x, y in _by_text.iteritems()])
+
+# Now that we've built the inverse map, we can add class aliases to
+# the _by_text mapping.
+
+_by_text.update({
+    'INTERNET' : IN,
+    'CHAOS' : CH,
+    'HESIOD' : HS
+    })
+
+_metaclasses = {
+    NONE : True,
+    ANY : True
+    }
+
+_unknown_class_pattern = re.compile('CLASS([0-9]+)$', re.I);
+
+class UnknownRdataclass(dns.exception.DNSException):
+    """Raised when a class is unknown."""
+    pass
+
+def from_text(text):
+    """Convert text into a DNS rdata class value.
+    @param text: the text
+    @type text: string
+    @rtype: int
+    @raises dns.rdataclass.UnknownRdataclass: the class is unknown
+    @raises ValueError: the rdata class value is not >= 0 and <= 65535
+    """
+
+    value = _by_text.get(text.upper())
+    if value is None:
+        match = _unknown_class_pattern.match(text)
+        if match == None:
+            raise UnknownRdataclass
+        value = int(match.group(1))
+        if value < 0 or value > 65535:
+            raise ValueError("class must be between >= 0 and <= 65535")
+    return value
+
+def to_text(value):
+    """Convert a DNS rdata class to text.
+    @param value: the rdata class value
+    @type value: int
+    @rtype: string
+    @raises ValueError: the rdata class value is not >= 0 and <= 65535
+    """
+
+    if value < 0 or value > 65535:
+        raise ValueError("class must be between >= 0 and <= 65535")
+    text = _by_value.get(value)
+    if text is None:
+        text = 'CLASS' + `value`
+    return text
+
+def is_metaclass(rdclass):
+    """True if the class is a metaclass.
+    @param rdclass: the rdata class
+    @type rdclass: int
+    @rtype: bool"""
+
+    if _metaclasses.has_key(rdclass):
+        return True
+    return False