def follow_line(instructions):
pos = Coord(0, 0)
for inst in instructions.split(','):
direction = inst[0]
distance = int(inst[1:])
for _ in range(distance):
if direction == 'U':
pos = pos.up()
elif direction == 'R':
pos = pos.right()
elif direction == 'D':
pos = pos.down()
elif direction == 'L':
pos = pos.left()
yield pos
