  Software verification is an important tool in establishing the reliability of
critical systems. One potential area of application is in the field of
robotics, as robots take on more tasks in both day-to-day areas and highly
specialised domains. Robots are usually given a plan to follow, if there are
errors in this plan the robot will not perform reliably. The capability to
check plans for errors in advance could prevent this. Python is a popular
programming language in the robotics domain, through the use of the Robot
Operating System (ROS) and various other libraries. Python's Turtle package
provides a mobile agent, which we formally model here using Communicating
Sequential Processes (CSP). Our interactive toolchain CSP2Turtle with CSP model
and Python components, enables Turtle plans to be verified in CSP before being
executed in Python. This means that certain classes of errors can be avoided,
and provides a starting point for more detailed verification of Turtle programs
and more complex robotic systems. We illustrate our approach with examples of
robot navigation and obstacle avoidance in a 2D grid-world.
