Switch to decimal.Decimal for money

Floating point data types are not suitable to represent money since
rounding issues will sum up.

1 files changed, 4 insertions, 3 deletions

diff --git a/finance/income.py b/finance/income.py
index 94759ff..8d775cb 100644
--- a/finance/income.py
+++ b/finance/income.py
@@ -1,17 +1,18 @@
 import dataclasses
 from datetime import datetime
+from decimal import Decimal
 
 
 @dataclasses.dataclass(kw_only=True, frozen=True)
 class Income:
     """Income models financial income paid on the first day of a month"""
 
-    amount: float
+    amount: Decimal
 
-    def integrate(self, start: datetime, end: datetime) -> float:
+    def integrate(self, start: datetime, end: datetime) -> Decimal:
         """Integrate the income from a start to an end date"""
 
-        retval = 0.0
+        retval = Decimal(0.0)
 
         current = datetime(start.year, start.month, 1)