Initialises plots of the environment.

def draw_plot(self):
        """ Initialises plots of the environment.
        """
        pylab.ion()
        fig = pylab.figure(1)

        # State plot.
#        state_axis = fig.add_subplot(3, 1, 1) # numrows, numcols, fignum
#        state_axis.title = 'State'
#        state_axis.xlabel = 'Time (hours)'
#        state_axis.grid = True
#        for i in range(self.state_data.shape[0]):
#            lines = state_axis.plot(self.state_data[i, 0], "g+-")
#            self.state_lines.append(lines[0])

        # Action plot.
#        action_axis = fig.add_subplot(3, 1, 2)
#        action_axis.title = 'Action'
#        action_axis.xlabel = 'Time (hours)'
#        action_axis.ylabel = 'Price ($/MWh)'
#        action_axis.grid = True
#        for i in range(self.action_data.shape[0]):
#            lines = action_axis.plot(self.action_data[i, 0], "ro-")
#            self.action_lines.append(lines[0])

        # Reward plot.
        reward_axis = fig.add_subplot(3, 1, 3)
#        reward_axis.title = 'Reward'
#        reward_axis.xlabel = 'Time (hours)'
#        reward_axis.ylabel = 'Earnings ($)'
#        reward_axis.grid(True)
        reward_lines = reward_axis.plot(self.reward_data[0, 0], [0], "mx-")
        self.reward_line = reward_lines[0]

        pylab.draw()