Fix SDK - openbb.ta.ma_chart - Command fails if index column is not labeled: "date". (#3556)

* fix date error

* add examples

openbb_terminal/common/technical_analysis/overlap_view.py

@@ -56,9 +56,21 @@ def view_ma(
         Format to export data
     external_axes: Optional[List[plt.Axes]], optional
         External axes (1 axis is expected in the list), by default None
+
+    Examples
+    --------
+    >>> from openbb_terminal.sdk import openbb
+    >>> df = openbb.stocks.load("AAPL")
+    >>> openbb.ta.ma_chart(data=df["Adj Close"], symbol="AAPL", ma_type="EMA", window=[20, 50, 100])
+
+
+    >>> from openbb_terminal.sdk import openbb
+    >>> spuk_index = openbb.economy.index(indices = ["^SPUK"])
+    >>> openbb.ta.ma_chart(data = spuk_index["^SPUK"], symbol = "S&P UK Index", ma_type = "EMA", window = [20, 50, 100])
     """
     # Define a dataframe for adding EMA series to it
     price_df = pd.DataFrame(data)
+    price_df.index.name = "date"
 
     l_legend = [symbol]
     if not window: