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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 pip_version(self):
 """ Get the pip version in the environment. Useful for knowing which args we can use when installing. """

        from .vendor.packaging.version import parse as parse_version
        pip = next(iter(
            pkg for pkg in self.get_installed_packages() if pkg.key == "pip"
        ), None)
        if pip is not None:
            pip_version = parse_version(pip.version)
        return parse_version("18.0")