Add docstring to ParametricUMAP placeholder class for better documentation

umap/__init__.py

@@ -1,42 +1,59 @@
-from warnings import warn, catch_warnings, simplefilter
-from .umap_ import UMAP
-
-try:
-    with catch_warnings():
-        simplefilter("ignore")
-        from .parametric_umap import ParametricUMAP, load_ParametricUMAP
-except ImportError:
-    warn(
-        "Tensorflow not installed; ParametricUMAP will be unavailable",
-        category=ImportWarning,
-    )
-
-    # Add a dummy class to raise an error
-    class ParametricUMAP(object):
-        def __init__(self, **kwds):
-            warn(
-                """The umap.parametric_umap package requires Tensorflow > 2.0 to be installed.
-            You can install Tensorflow at https://www.tensorflow.org/install
-
-            or you can install the CPU version of Tensorflow using 
-
-            pip install umap-learn[parametric_umap]
-
-            """
-            )
-            raise ImportError(
-                "umap.parametric_umap requires Tensorflow >= 2.0"
-            ) from None
-
-
-from .aligned_umap import AlignedUMAP
-
-# Workaround: https://github.com/numba/numba/issues/3341
-import numba
-
-from importlib.metadata import version, PackageNotFoundError
-
-try:
-    __version__ = version("umap-learn")
-except PackageNotFoundError:
-    __version__ = "0.5-dev"
+from warnings import warn, catch_warnings, simplefilter
+from .umap_ import UMAP
+
+try:
+    with catch_warnings():
+        simplefilter("ignore")
+        from .parametric_umap import ParametricUMAP, load_ParametricUMAP
+except ImportError:
+    warn(
+        "Tensorflow not installed; ParametricUMAP will be unavailable",
+        category=ImportWarning,
+    )
+
+    # Add a dummy class to raise an error
+    class ParametricUMAP(object):
+        """A placeholder class for ParametricUMAP when TensorFlow is not installed.
+
+        This class provides a graceful error message when users attempt to instantiate
+        ParametricUMAP without having TensorFlow installed. The real implementation
+        requires TensorFlow >= 2.0 and is loaded from umap.parametric_umap.
+
+        Examples
+        --------
+        >>> try:
+        ...     from umap import ParametricUMAP
+        ... except ImportError:
+        ...     pass  # TensorFlow not available
+
+        See Also
+        --------
+        load_ParametricUMAP : Load a saved ParametricUMAP model
+        """
+        def __init__(self, **kwds):
+            warn(
+                """The umap.parametric_umap package requires Tensorflow > 2.0 to be installed.
+            You can install Tensorflow at https://www.tensorflow.org/install
+
+            or you can install the CPU version of Tensorflow using 
+
+            pip install umap-learn[parametric_umap]
+
+            """
+            )
+            raise ImportError(
+                "umap.parametric_umap requires Tensorflow >= 2.0"
+            ) from None
+
+
+from .aligned_umap import AlignedUMAP
+
+# Workaround: https://github.com/numba/numba/issues/3341
+import numba
+
+from importlib.metadata import version, PackageNotFoundError
+
+try:
+    __version__ = version("umap-learn")
+except PackageNotFoundError:
+    __version__ = "0.5-dev"