chore: convert DatasetDict to dict and add __repr__ for Dataset

src/phoenix/datasets/dataset.py

@@ -90,6 +90,9 @@ def __init__(
         self.to_disc()
         logger.info(f"""Dataset: {self.__name} initialized""")
 
+    def __repr__(self) -> str:
+        return f'<Dataset "{self.name}">'
+
     @cached_property
     def start_time(self) -> datetime:
         """Returns the datetime of the earliest inference in the dataset"""

src/phoenix/datasets/fixtures.py

@@ -1,7 +1,7 @@
 import logging
 import os
 from dataclasses import dataclass, replace
-from typing import Dict, Tuple
+from typing import Tuple
 
 from pandas import read_parquet
 
@@ -325,9 +325,10 @@ def _download_and_persist_dataset_if_missing(
     return dataset
 
 
-@dataclass(frozen=True)
-class DatasetDict(Dict[str, Dataset]):
-    """A dictionary of datasets, split out by dataset type (primary, reference)."""
+class DatasetDict(dict):  # type: ignore
+    """
+    A dictionary of datasets, split out by dataset type (primary, reference).
+    """
 
     primary: Dataset
     reference: Dataset