Decouple fetching metadata

spotdl/lyrics/lyric_base.py

@@ -5,10 +5,25 @@ from abc import abstractmethod
 
 
 class LyricBase(ABC):
+    """
+    Defined lyric providers must inherit from this abstract base
+    class and implement their own functionality for the below
+    defined methods.
+    """
+
     @abstractmethod
     def __init__(self, artist, track):
+        """
+        This method must set any protected attributes,
+        which may be modified from outside the class
+        if the need arises.
+        """
         pass
 
     @abstractmethod
     def get_lyrics(self, linesep="\n", timeout=None):
+        """
+        This method must return the lyrics string for the
+        given track.
+        """
         pass