code: def is_convertible_with(self, other):
          
          other = as_dimension(other)
          return self._value is None or other.value is None or self._value == other.value
docs: Returns true if `other` is convertible with this Dimension.
  
          Two known Dimensions are convertible if they have the same value.
          An unknown Dimension is convertible with all other Dimensions.
  
          Args:
            other: Another Dimension.
  
          Returns:
            True if this Dimension and `other` are convertible.