diff --git a/third_party/2and3/dateutil/_common.pyi b/third_party/2and3/dateutil/_common.pyi
index 19504613c..1311a175e 100644
--- a/third_party/2and3/dateutil/_common.pyi
+++ b/third_party/2and3/dateutil/_common.pyi
@@ -9,5 +9,7 @@ class weekday(object):
 
     def __repr__(self) -> str: ...
 
+    def __hash__(self) -> int: ...
+
     weekday: int
     n: int
diff --git a/third_party/2and3/dateutil/parser.pyi b/third_party/2and3/dateutil/parser.pyi
index 25949d834..045a7934d 100644
--- a/third_party/2and3/dateutil/parser.pyi
+++ b/third_party/2and3/dateutil/parser.pyi
@@ -33,6 +33,8 @@ class parser(object):
               ignoretz: bool = ..., tzinfos: Optional[Mapping[Text, tzinfo]] = ...,
               **kwargs: Any) -> datetime: ...
 
+def isoparse(dt_str: Union[str, bytes, IO[str], IO[bytes]]) -> datetime: ...
+
 DEFAULTPARSER: parser
 def parse(timestr: _FileOrStr, parserinfo: Optional[parserinfo] = ..., **kwargs: Any) -> datetime: ...
 class _tzparser: ...
diff --git a/third_party/2and3/dateutil/relativedelta.pyi b/third_party/2and3/dateutil/relativedelta.pyi
index 7b33513c0..40ee586ff 100644
--- a/third_party/2and3/dateutil/relativedelta.pyi
+++ b/third_party/2and3/dateutil/relativedelta.pyi
@@ -87,3 +87,5 @@ class relativedelta(object):
     def __div__(self: _SelfT, other: SupportsFloat) -> _SelfT: ...
     def __truediv__(self: _SelfT, other: SupportsFloat) -> _SelfT: ...
     def __repr__(self) -> str: ...
+    def __abs__(self: _SelfT) -> _SelfT: ...
+    def __hash__(self) -> int: ...
diff --git a/third_party/2and3/dateutil/tz/__init__.pyi b/third_party/2and3/dateutil/tz/__init__.pyi
index 1ef0c4270..5a5e45feb 100644
--- a/third_party/2and3/dateutil/tz/__init__.pyi
+++ b/third_party/2and3/dateutil/tz/__init__.pyi
@@ -9,6 +9,7 @@ from .tz import (
     gettz as gettz,
     datetime_exists as datetime_exists,
     datetime_ambiguous as datetime_ambiguous,
+    resolve_imaginary as resolve_imaginary,
 )
 
 UTC: tzutc
diff --git a/third_party/2and3/dateutil/tz/tz.pyi b/third_party/2and3/dateutil/tz/tz.pyi
index 23ea63d17..71395070f 100644
--- a/third_party/2and3/dateutil/tz/tz.pyi
+++ b/third_party/2and3/dateutil/tz/tz.pyi
@@ -31,6 +31,9 @@ class tzoffset(datetime.tzinfo):
     def __ne__(self, other): ...
     __reduce__: Any
 
+    @classmethod
+    def instance(cls, name, offset) -> tzoffset: ...
+
 class tzlocal(_tzinfo):
     def __init__(self) -> None: ...
     def utcoffset(self, dt: Optional[datetime.datetime]) -> Optional[datetime.timedelta]: ...
@@ -70,6 +73,9 @@ class tzstr(tzrange):
     hasdst: bool
     def __init__(self, s: Union[bytes, _FileObj], posix_offset: bool = ...) -> None: ...
 
+    @classmethod
+    def instance(cls, name, offset) -> tzoffset: ...
+
 class tzical:
     def __init__(self, fileobj: _FileObj) -> None: ...
     def keys(self): ...
@@ -78,6 +84,13 @@ class tzical:
 TZFILES: List[str]
 TZPATHS: List[str]
 
-def gettz(name: Optional[Text] = ...) -> Optional[datetime.tzinfo]: ...
 def datetime_exists(dt: datetime.datetime, tz: Optional[datetime.tzinfo] = ...) -> bool: ...
 def datetime_ambiguous(dt: datetime.datetime, tz: Optional[datetime.tzinfo] = ...) -> bool: ...
+def resolve_imaginary(dt: datetime.datetime) -> datetime.datetime: ...
+
+
+class _GetTZ:
+    def __call__(self, name: Optional[Text] = ...) -> Optional[datetime.tzinfo]: ...
+    def nocache(self, name: Optional[Text]) -> Optional[datetime.tzinfo]: ...
+
+gettz: _GetTZ
diff --git a/third_party/2and3/dateutil/utils.pyi b/third_party/2and3/dateutil/utils.pyi
new file mode 100644
index 000000000..b722053e4
--- /dev/null
+++ b/third_party/2and3/dateutil/utils.pyi
@@ -0,0 +1,7 @@
+from typing import Optional
+from datetime import datetime, tzinfo, timedelta
+
+
+def default_tzinfo(dt: datetime, tzinfo: tzinfo) -> datetime: ...
+def today(tzinfo: Optional[tzinfo] = ...) -> datetime: ...
+def within_delta(dt1: datetime, dt2: datetime, delta: timedelta) -> bool: ...