Minor fix

asset_backtester/__init__.py

@@ -1,2 +1 @@
-from backtester import Backtest
-from signal import Signal, get_order
+from .backtester import Backtest

asset_backtester/backtester.py

@@ -1,7 +1,7 @@
 import pandas as pd
 import pyprind
 
-from portfolio.portfolio import Portfolio
+from portfolio import Portfolio
 
 
 class Backtest:

asset_backtester/portfolio/portfolio.py

@@ -1,11 +1,8 @@
-from .direction import Direction
 from .asset import Asset
 
 
 class Portfolio:
-    def __init__(self, direction=Direction.BUY):
-        assert isinstance(direction, Direction)
-        self.direction = direction
+    def __init__(self):
         self.assets = []
 
     def add_asset(self, asset):