Catch ValueError in module available (#615)

* Catch ValueError in module available

* Update CHANGELOG

CHANGELOG.md

@@ -40,10 +40,12 @@ The format is based on [Keep a Changelog](http://keepachangelog.com/en/1.0.0/).
 
 ### Fixed
 
-
 - Fixed a bug where serve sanity checking would not be triggered using the latest PyTorchLightning version ([#493](https://github.com/PyTorchLightning/lightning-flash/pull/493))
+
 - Fixed a bug where train and validation metrics weren't being correctly computed ([#559](https://github.com/PyTorchLightning/lightning-flash/pull/559))
 
+- Fixed a bug where an uncaught ValueError could be raised when checking if a module is available ([#615](https://github.com/PyTorchLightning/lightning-flash/pull/615))
+
 ## [0.4.0] - 2021-06-22
 
 ### Added

flash/core/utilities/imports.py

@@ -43,6 +43,9 @@ def _module_available(module_path: str) -> bool:
     except ModuleNotFoundError:
         # Python 3.7+
         return False
+    except ValueError:
+        # Sometimes __spec__ can be None and gives a ValueError
+        return True
 
 
 def _compare_version(package: str, op, version) -> bool:
@@ -59,7 +62,7 @@ def _compare_version(package: str, op, version) -> bool:
     try:
         pkg_version = Version(pkg.__version__)
     except TypeError:
-        # this is mock by sphinx, so it shall return True ro generate all summaries
+        # this is mock by sphinx, so it shall return True to generate all summaries
         return True
     return op(pkg_version, Version(version))