title: Invalid syntax error in simple Python-3 program
body: <pre><code>from TurtleWorld import *
  import math
  
  bob = Turtle()
  print(bob)
  
  draw_circle(turtle, r):
      d = r*2
      c = d*math.pi
      degrees = 360/25
      length = c // 25
      for i in range(25):
          fd(turtle, length)
          rt(turtle, degrees)
  
  draw_circle(bob, 25)
  
  wait_for_user()
  </code></pre>
  
  <hr>
  
  <p>The problem in on line 7:</p>
  
  <blockquote>
    <p>draw_circle(turtle, r):</p>
  </blockquote>
  
  <p>The compiler only tells me that there is a syntax error and highlights the colon at the
  end of that line.
  I'm sure I'm missing something simple, but the code looks right to me.</p>