matplotlib.pyplot GRAPH ERROR

import pandas as pd
    import matplotlib.pyplot as plt
GFG = pd.read_csv("C:/Users/Usuario/Desktop/algotrade/GFG11.BA.csv",decimal=","
                  ,sep=";", parse_dates=["Date"],  
                  dayfirst=True, index_col='Date')
# Definimos las medias
    short_window = 12
    long_window = 26
# Armamos la 'signals' DataFrame con la columna 'signal'
    signals = pd.DataFrame(index=GFG.index)
    signals['signal'] = 0.0
# creamos el promedio corto sobre la ventana
    signals['short_mavg'] = GFG['Close'].rolling(window=short_window, min_periods=1,center=False).mean()
# Creamos la media larga
    signals['long_mavg'] = GFG['Close'].rolling(window=long_window, min_periods=1,center=False).mean()
# Creamos la senal
    signals['signal'][short_window:]=np.where(signals['short_mavg'][short_window:]>signals['long_mavg'][short_window:],1.0, 0.0)   
# Generamos las senales
    signals['positions'] = signals['signal'].diff()
# Print 'signals'
    print(signals)
# Iniciamos la figura a pintar
    fig = plt.figure()
# agregamos un subplot y una etiqueta a y
    ax1 = fig.add_subplot(111,  ylabel='Price in $')
# pintamos el grafico de cierre
    GFG['Close'].plot(ax=ax1, color='r', lw=2.)
# Pitamos medias largas y cortas
    signals[['short_mavg', 'long_mavg']].plot(ax=ax1, lw=2.)
# Pintamos las senales de compra
    ax1.plot(signals.loc[signals.positions == 1.0].index, 
             signals.short_mavg[signals.positions == 1.0],
            '^', markersize=10, color='m')
# Pintamos senales de venta
    ax1.plot(signals.loc[signals.positions == -1.0].index, 
             signals.short_mavg[signals.positions == -1.0],
            'v', markersize=10, color='k')
# show me the graph
    plt.show()

My question is: Why do not you show me the graph?