Get a layer in the Overlay.

        Get a particular layer in the Overlay using its path string
        or an integer index.

        Args:
            identifier: Index or path string of the item to return
            default: Value to return if no item is found

        Returns:
            The indexed layer of the Overlay

def get(self, identifier, default=None):
        """Get a layer in the Overlay.

        Get a particular layer in the Overlay using its path string
        or an integer index.

        Args:
            identifier: Index or path string of the item to return
            default: Value to return if no item is found

        Returns:
            The indexed layer of the Overlay
        """
        if isinstance(identifier, int):
            values = list(self.data.values())
            if 0 <= identifier < len(values):
                return values[identifier]
            else:
                return default
        return super(Overlay, self).get(identifier, default)