def GetCircle(pos):
  """Gets the circle (center, radius) that goes through the two
  endpoints of the current time extent (x=pos[0]) and just touches the
  left edge of the screen. Also computes the degrees (in radians) of
  the small arc through the three points.

  Returns (center, radius, arc-degrees).
  """
  if pos[0] == 0:
    pos[0] = 1
  a, b = float(pos[0]), 0.0
  c, d = 0.0, iphone_dims[1]/2.0
  e, f = float(pos[0]), float(iphone_dims[1])
  k = (0.5)*((a**2+b**2)*(e-c) + (c**2+d**2)*(a-e) + (e**2+f**2)*(c-a)) / (b*(e-c)+d*(a-e)+f*(a-c))
  h = (0.5)*((a**2+b**2)*(f-d) + (c**2+d**2)*(b-f) + (e**2+f**2)*(d-b)) / (a*(f-d)+c*(b-f)+e*(d-b))
  rsqr = (a-h)**2 + (b-k)**2

  theta = math.acos(((a-h)*(e-h) + (b-k)*(f-k)) / rsqr)
  return ((h, k), math.sqrt(rsqr), theta)
dataset/ETHPy150Open viewfinderco/viewfinder/clients/experimental/viewfinder.py/GetCircle/swapped operands of `-`