code: def find(cls, family_name, is_bold, is_italic):
          
          if cls._font_files is None:
              cls._font_files = cls._installed_fonts()
          return cls._font_files[(family_name, is_bold, is_italic)]
docs: Return the absolute path to the installed OpenType font having
          *family_name* and the styles *is_bold* and *is_italic*.