From 62ceca67a32bffc3dcacec4653a5c04c7f398102 Mon Sep 17 00:00:00 2001
From: Austin Weisgrau <austinweisgrau@gmail.com>
Date: Mon, 5 Feb 2024 14:04:43 -0800
Subject: [PATCH] Allow Table(None)

---
 parsons/etl/table.py | 24 ++----------------------
 test/test_etl.py     |  5 ++---
 2 files changed, 4 insertions(+), 25 deletions(-)

diff --git a/parsons/etl/table.py b/parsons/etl/table.py
index 28a6b6cd0..edbdfa316 100644
--- a/parsons/etl/table.py
+++ b/parsons/etl/table.py
@@ -1,6 +1,5 @@
 import logging
 import pickle
-from enum import Enum
 from typing import Union
 
 import petl
@@ -14,20 +13,6 @@
 DIRECT_INDEX_WARNING_COUNT = 10
 
 
-class _EmptyDefault(Enum):
-    """Default argument for Table()
-
-    This is used because Table(None) should not be allowed, but we
-    need a default argument that isn't the mutable []
-
-    See https://stackoverflow.com/a/76606310 for discussion."""
-
-    token = 0
-
-
-_EMPTYDEFAULT = _EmptyDefault.token
-
-
 class Table(ETL, ToFrom):
     """
     Create a Parsons Table. Accepts one of the following:
@@ -46,16 +31,11 @@ class Table(ETL, ToFrom):
 
     def __init__(
         self,
-        lst: Union[list, tuple, petl.util.base.Table, _EmptyDefault] = _EMPTYDEFAULT,
+        lst: Union[list, tuple, petl.util.base.Table, None] = None,
     ):
         self.table = None
 
-        # Normally we would use None as the default argument here
-        # Instead of using None, we use a sentinal
-        # This allows us to maintain the existing behavior
-        # This is allowed: Table()
-        # This should fail: Table(None)
-        if lst is _EMPTYDEFAULT:
+        if lst is None:
             self.table = petl.fromdicts([])
 
         elif isinstance(lst, list) or isinstance(lst, tuple):
diff --git a/test/test_etl.py b/test/test_etl.py
index 89d8598ab..fa8e0dad0 100644
--- a/test/test_etl.py
+++ b/test/test_etl.py
@@ -67,9 +67,8 @@ def test_from_invalid_list(self):
         self.assertRaises(ValueError, Table, list_of_invalid)
 
     def test_from_empty_petl(self):
-        # This test ensures that this would fail: Table(None)
-        # Even while allowing Table() to work
-        self.assertRaises(ValueError, Table, None)
+        # Just ensure this doesn't throw an error
+        Table(None)
 
     def test_from_empty_list(self):
         # Just ensure this doesn't throw an error