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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def remove_stage_from_deployed_values(key, filename):
 # type: (str, str) -> None """Delete a top level key from the deployed JSON file."""

    final_values = {}  # type: Dict[str, Any]
    try:
        with open(filename, 'r') as f:
            final_values = json.load(f)
    except IOError:
        # If there is no file to delete from, then this funciton is a noop.
        return

    try:
        del final_values[key]
        with open(filename, 'wb') as f:
            data = serialize_to_json(final_values)
            f.write(data.encode('utf-8'))
    except KeyError:
        # If they key didn't exist then there is nothing to remove.
        pass