parameters: (self, id, new_val)
docstring: Sets the option value for the specified size `id`.
  
          :param integer `id`: the identification bit for the size value;
          :param input`new_val`: the new value for the size.
  
          :raise: `Exception` if the `id` is not recognized.        
  
          :see: :meth:`~BPArt.GetMetric` for a list of meaningful size ids.
docstring_summary: Sets the option value for the specified size `id`.
docstring_tokens: Sets the option value for the specified size id .
function: def SetMetric(self, id, new_val):
          """
          Sets the option value for the specified size `id`.
  
          :param integer `id`: the identification bit for the size value;
          :param input`new_val`: the new value for the size.
  
          :raise: `Exception` if the `id` is not recognized.        
  
          :see: :meth:`~BPArt.GetMetric` for a list of meaningful size ids.        
          """
  
          if id == BP_SEPARATOR_SIZE:
              self._separator_size = new_val
          elif id == BP_MARGINS_SIZE:
              self._margins_size = new_val
          elif id == BP_BORDER_SIZE:
              self._caption_border_size = new_val
              self._border_pen.SetWidth(new_val)
          elif id == BP_PADDING_SIZE:
              self._padding_size = new_val
          else:
              raise Exception("\nERROR: Invalid Metric Ordinal. ")
function_tokens: def SetMetric ( self , id , new_val ) : if id == BP_SEPARATOR_SIZE : self . _separator_size = new_val elif id == BP_MARGINS_SIZE : self . _margins_size = new_val elif id == BP_BORDER_SIZE : self . _caption_border_size = new_val self . _border_pen . SetWidth ( new_val ) elif id == BP_PADDING_SIZE : self . _padding_size = new_val else : raise Exception ( "\nERROR: Invalid Metric Ordinal. " )