chore: delete dead code in project context (#770)

src/dsp_tools/commands/project/models/context.py

@@ -99,21 +99,9 @@ def __init__(self, context: Optional[dict[str, str]] = None):
 
         self._rcontext = {v.iri: k for k, v in self._context.items()}
 
-    def __len__(self) -> int:
-        return len(self._context)
-
     def __getitem__(self, key: str) -> OntoIri:
         return self._context[key]
 
-    def __setitem__(self, key: str, value: OntoIri) -> None:
-        self._context[key] = value
-        self._rcontext[value.iri] = key
-
-    def __delitem__(self, key: str) -> None:
-        iri = self._context[key].iri
-        del self._context[key].iri
-        del self._rcontext[iri]
-
     def __contains__(self, key: str) -> bool:
         return key in self._context