chore: import upstream snapshot with attribution

basics/base_vocoder.py

@@ -0,0 +1,23 @@
+class BaseVocoder:
+    def to_device(self, device):
+        """
+        
+        :param device: torch.device or str
+        """
+        raise NotImplementedError()
+
+    def get_device(self):
+        """
+        
+        :return: device: torch.device or str
+        """
+        raise NotImplementedError()
+    
+    def spec2wav(self, mel, **kwargs):
+        """
+
+        :param mel: [T, 80]
+        :return: wav: [T']
+        """
+
+        raise NotImplementedError()