Add an explicit repr to PythonDataSource.

Fixes: #5634
PiperOrigin-RevId: 690935467

Author: marcenacp

tensorflow_datasets/core/data_sources/python.py

@@ -22,7 +22,7 @@
 from typing import Any, Callable
 
 
-@dataclasses.dataclass
+@dataclasses.dataclass(repr=False)
 class PythonDataSource(MappingView, Sequence):
   """Python data source backed by Python objects: length and __getitem__."""
 
@@ -41,3 +41,6 @@ def __iter__(self):
 
   def __getitem__(self, i: int) -> Any:
     return self.getitem(i)
+
+  def __repr__(self) -> str:
+    return f'PythonDataSource(length={self.length})'

tensorflow_datasets/core/data_sources/python_test.py

@@ -54,3 +54,8 @@ def test_tree_map_structure():
   tree.map_structure(func, source)
   calls = [mock.call(0), mock.call(1), mock.call(2)]
   func.assert_has_calls(calls)
+
+
+def test_repr():
+  source = python.PythonDataSource(length=3, getitem=getitem)
+  assert repr(source) == 'PythonDataSource(length=3)'