code: def fix_shape(source):
      
      if source.a < source.b:
          source.a, source.b = source.b, source.a
          source.err_a, source.err_b = source.err_b, source.err_a
          source.pa += 90
      return
docs: Ensure that a>=b for a given source object.
      If a<b then swap a/b and increment pa by 90.
      err_a/err_b are also swapped as needed.
  
      Parameters
      ----------
      source : object
          any object with a/b/pa/err_a/err_b properties