add exception condition for invalid type given on isub MusifyCollection

.flake8

@@ -1,5 +1,5 @@
 [flake8]
-extend-exclude = .venv* jupyter/ notebooks/
+extend-exclude = .venv* jupyter/ notebooks/ test.py
 extend-ignore = E266
 per-file-ignores =
     **/__init__.py:F401

.gitignore

@@ -149,3 +149,5 @@ _site
 .jekyll-cache
 .jekyll-metadata
 vendor
+
+test.py

docs/index.rst

@@ -49,6 +49,7 @@ Should you wish to take advantage of some or all of this functionality, install
    pip install musify[bars]  # dependencies for displaying progress bars on longer running processes
    pip install musify[images]  # dependencies for processing images
    pip install musify[musicbee]  # dependencies for working with a local MusicBee library and its playlist types
+   pip install musify[sqlite]  # dependencies for working with a SQLite cache backend for caching API responses
 
    # or you may install any combination of these e.g.
    pip install musify[bars,images,musicbee]

musify/libraries/core/collection.py

@@ -304,6 +304,9 @@ def __sub__(self, __items: Iterable[T]):
         return items
 
     def __isub__(self, __items: Iterable[T]):
+        if not isinstance(__items, Iterable):
+            raise MusifyTypeError("You must provide an iterable object to use this functionality.")
+
         for item in __items:
             self.remove(item)
         return self

musify/libraries/remote/core/library.py

@@ -452,7 +452,7 @@ async def sync(
         log_kind = "adding new items only"
         if kind != "new":
             log_kind = 'all' if kind == 'refresh' else 'extra'
-            log_kind = f"clearing {log_kind} items from {self.api.source} playlist first"
+            log_kind = f"clearing {log_kind} items from each {self.api.source} playlist first"
         self.logger.info(
             f"\33[1;95m ->\33[1;97m Synchronising {len(playlists)} {self.api.source} playlists: {log_kind}"
             f"{f' and reloading stored playlists' if reload else ''} \33[0m"