code: def normalizeInterpolationFactor(value):
      
      if not isinstance(value, (int, float, list, tuple)):
          raise TypeError("Interpolation factor must be an int, float, or tuple "
                          "instances, not %s." % type(value).__name__)
      if isinstance(value, (int, float)):
          value = (float(value), float(value))
      else:
          if not len(value) == 2:
              raise ValueError("Interpolation factor tuple must contain two "
                               "values, not %d." % len(value))
          for v in value:
              if not isinstance(v, (int, float)):
                  raise TypeError("Interpolation factor tuple values must be an "
                                  ":ref:`type-int-float`, not %s."
                                  % type(value).__name__)
          value = tuple([float(v) for v in value])
      return value
docs: Normalizes interpolation factor.
  
      * **value** must be an :ref:`type-int-float`, ``tuple`` or ``list``.
      * If **value** is a ``tuple`` or ``list``, it must have exactly two items.
        These items must be instances of :ref:`type-int-float`.
      * Returned value is a ``tuple`` of two ``float``.