Show both MACD and indicator strat on figure

Prepare for strategy learner.

strategy_evaluation/indicators.py

@@ -73,7 +73,7 @@ def rsi(df, symbol, period=14):
                            (avg_loss / period))))
         return rsi
 
-    key = f"rsi"
+    key = "rsi"
     # Add one to get 'period' price changes (first change is nan).
     period += 1
     df[key] = df[symbol].rolling(period).apply(rsi)
@@ -91,13 +91,6 @@ def macd(df, symbol):
     return df[[k1, k2, k3]]
 
 
-def price_delta(df, symbol, period=1):
-    """Calculate delta between previous day and today."""
-    k = f"diff_{period}"
-    df[k] = df[symbol].diff(periods=period)
-    return df[k]
-
-
 def price_delta(df, symbol, period=1):
     """Calculate percentage change for period."""
     k = f"pct_{period}"