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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_package_name(pkg_name: str) -> None: """ Raise an exception if the value is not a valid package name as defined in the EthPM-Spec. """

    if not bool(re.match(PACKAGE_NAME_REGEX, pkg_name)):
        raise ValidationError(f"{pkg_name} is not a valid package name.")