Draw Move

Next, we need a way to draw a path between 2 cells.

Assignment

Create a draw_move method that draws a line from the center of one cell to the center of another. The method definition should look something like this:

def draw_move(self, to_cell, undo=False):

If the undo flag is not set, the line you draw should be "red". Otherwise, make it "gray". This way as we're drawing a path through the maze, it will be a nice red color, but if we need to backtrack, it will be gray.
Use the x/y coordinates of the 2 cells in question to decide how to draw the line connecting the two cells.

Again, test this manually by creating cells and drawing moves between them.