Get the note for the cell at the given coordinates.

    coords is a tuple of (col, row)

def get_note(self, coords):
    """Get the note for the cell at the given coordinates.

    coords is a tuple of (col, row)
    """
    col, row = coords
    note = self.raw_sheet.cell_note_map.get((row, col))
    return note.text if note else None