I want to open a window with pyqtgraph alone, without using pyqt.

I want to create two or more axes in one window through pyqtgraph, and draw two lines in one ax.
What should I do?

The following code creates multiple windows.

import pandas as pd
import pyqtgraph as pg

a = [
    {'a': 5, 'b': 10, 'c': 5},
    {'a': 4, 'b': 0.5, 'c': 1},
    {'a': 3.5, 'b': 15, 'c': 9},
    {'a': 2.1, 'b': 5, 'c': 8},
    {'a': 0.1, 'b': 1, 'c': 5},
]

df = pd.DataFrame(a)
pg.plot(df['a'].values)
pg.plot(df['b'].values)
pg.exec()

The following code does not create a window.

import pandas as pd
import pyqtgraph as pg

a = [
    {'a': 5, 'b': 10, 'c': 5},
    {'a': 4, 'b': 0.5, 'c': 1},
    {'a': 3.5, 'b': 15, 'c': 9},
    {'a': 2.1, 'b': 5, 'c': 8},
    {'a': 0.1, 'b': 1, 'c': 5},
]

df = pd.DataFrame(a)
widget = pg.MultiPlotWidget()
widget.addItem(pg.PlotWidget(df['a'].values))
widget.addItem(pg.PlotWidget(df['b'].values))
pg.exec()