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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 validate_depth(self, depth: DepthDefinitionType) -> Optional[int]: """ Converts the depth to int and validates that the value can be used. :raise ValueError: If the provided depth is not valid """

        if depth is not None:
            try:
                depth = int(depth)
            except ValueError:
                raise ValueError(f"Depth '{depth}' can't be converted to int.")

            if depth < 1:
                raise ValueError(f"Depth '{depth}' isn't a positive number")

            return depth
        return None