<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def clear_diagram(self, diagram):
 """Clear diagram. Parameters diagram : [column, row] Diagram to clear. """

        plot = self.subplots[diagram[1]][diagram[0]]
        plot.cla()