[SYSTEMDS-3802] Conditionally Load Scuro

This commits refine the __init__.py file for systemds, to conditionally
load the Scuro library. Previeously, more packages would have to be installed
to run SystemDS via the Python API. Now it is more lean with an informative
warning listing the required packages if Scuro is required.

Closes #2150

Author: christinadionysio

src/main/python/systemds/__init__.py

@@ -18,10 +18,46 @@
 # under the License.
 #
 # -------------------------------------------------------------
-
+from importlib.metadata import version, PackageNotFoundError
 from systemds import context
 from systemds import operator
 from systemds import examples
-from systemds import scuro
 
-__all__ = ["context", "operator", "examples", "scuro"]
+__all__ = ["context", "operator", "examples"]
+
+required_packages = [
+    ("torch", "2.5.1"),
+    ("torchvision", "0.20.1"),
+    ("librosa", "0.10.2"),
+    ("opencv-python", "4.10.0.84"),
+    ("opt-einsum", "3.3.0"),
+    ("h5py", "3.11.0"),
+    ("transformers", "4.46.3"),
+    ("nltk", "3.9.1"),
+    ("gensim", "4.3.3"),
+]
+
+
+def check_package_version(package_name, required_version):
+    try:
+        return version(package_name) >= required_version
+    except PackageNotFoundError:
+        return False
+
+
+if all(check_package_version(pkg, version) for pkg, version in required_packages):
+    try:
+        from systemds import scuro
+
+        __all__.append("scuro")
+    except ImportError as e:
+        print(f"Scuro could not be imported: {e}")
+else:
+    missing = [
+        f"{pkg} {version}"
+        for pkg, version in required_packages
+        if not check_package_version(pkg, version)
+    ]
+    print(
+        f"Warning: Scuro dependencies missing or wrong version installed: {', '.join(missing)}"
+    )