code: def is_compatible(self, obj):
          
          both_unicode_mapped = isinstance(self._text, str) and isinstance(obj._text, str)
          try:
              if both_unicode_mapped:
                  return self.rendermode == obj.rendermode
              font0, _ = self._text
              font1, _ = obj._text
              return font0 == font1 and self.rendermode == obj.rendermode
          except (ValueError, AttributeError):
              return False
docs: Check if characters can be combined into a textline
  
          We consider characters compatible if:
              - the Unicode mapping is known, and both have the same render mode
              - the Unicode mapping is unknown but both are part of the same font