diff --git a/fin_defs/__init__.py b/fin_defs/__init__.py
index dc716c4..2cf05d2 100644
--- a/fin_defs/__init__.py
+++ b/fin_defs/__init__.py
@@ -505,6 +505,7 @@ class AssetInformation:
 
 THREE_DECIMALS_UNDER_THIS_AMOUNT = 0.10
 
+
 def assert_same_asset(do: str, a_asset: 'AssetAmount', b_asset: 'AssetAmount'):
     if a_asset.asset != b_asset.asset:
         msg = f'Attempting to {do} {a_asset} and {b_asset}, but these must have the same asset'
@@ -568,7 +569,6 @@ class AssetAmount:
         assert_same_asset('subtract', self, other)
         return AssetAmount(self.asset, self.amount - other.amount)
 
-
     def __truediv__(self, other: 'Decimal | AssetAmount') -> 'Decimal | AssetAmount':
         if isinstance(other, AssetAmount):
             assert_same_asset('divide', self, other)
diff --git a/test/test_asset_amount.py b/test/test_asset_amount.py
index 6c988a6..28be708 100644
--- a/test/test_asset_amount.py
+++ b/test/test_asset_amount.py
@@ -1,5 +1,5 @@
-from decimal import Decimal
 import re
+from decimal import Decimal
 
 import pytest
 
@@ -84,7 +84,9 @@ def test_add_wrong_type():
 def test_add_wrong_asset():
     with pytest.raises(
         ValueError,
-        match=re.escape('Attempting to add $20.00 USD and 21.00 DKK, but these must have the same asset'),
+        match=re.escape(
+            'Attempting to add $20.00 USD and 21.00 DKK, but these must have the same asset',
+        ),
     ):
         assert USD_20 + DKK_21
 
@@ -97,7 +99,9 @@ def test_sub_wrong_type():
 def test_sub_wrong_asset():
     with pytest.raises(
         ValueError,
-        match=re.escape('Attempting to subtract $20.00 USD and 21.00 DKK, but these must have the same asset'),
+        match=re.escape(
+            'Attempting to subtract $20.00 USD and 21.00 DKK, but these must have the same asset',
+        ),
     ):
         assert USD_20 - DKK_21
 
@@ -110,7 +114,9 @@ def test_cmp_wrong_type():
 def test_cmp_wrong_asset():
     with pytest.raises(
         ValueError,
-        match=re.escape('Attempting to compare $20.00 USD and 21.00 DKK, but these must have the same asset'),
+        match=re.escape(
+            'Attempting to compare $20.00 USD and 21.00 DKK, but these must have the same asset',
+        ),
     ):
         assert USD_20 < DKK_21
 
@@ -118,6 +124,8 @@ def test_cmp_wrong_asset():
 def test_div_wrong_asset():
     with pytest.raises(
         ValueError,
-        match=re.escape('Attempting to divide $21.00 USD and 21.00 DKK, but these must have the same asset'),
+        match=re.escape(
+            'Attempting to divide $21.00 USD and 21.00 DKK, but these must have the same asset',
+        ),
     ):
         assert USD_21 / DKK_21