Linear line with matplotlib - line graph

Power BI has Python visual where I can use Python code to create the visual. I am using the matplotlib and trying to create the visuals in power bi. It works fine but it is not connecting the lines as needed. Here is the code.

dataset = pandas.DataFrame(R_Length, ScatterPlot, ClusterLine, TargetLine)dataset = dataset.drop_duplicates()import matplotlib.pyplot as plt ax = plt.gca()dataset.plot(kind='scatter', x='R_Length', y='ScatterPlot', color='blue',ax=ax)dataset.plot(kind='line', x='R_Length', y='ClusterLine', color='black', linestyle='solid', fillstyle='full' ,ax=ax)dataset.plot(kind='line', x='R_Length', y='TargetLine', color='red', linestyle='-' ,ax=ax)plt.show()

The visual it created looks like this (below). Black and Red line is not connected.

Its should look like this. Black and Red lines are connected.

Any help is appreciated.Thanks.