Installs and verifies package manager

def __get_package_manager(self):
        """
        Installs and verifies package manager
        """
        package_manager = ""
        args = ""
        sudo_required = True
        if system.is_osx():
            package_manager = "brew"
            sudo_required = False
            args = " install"
        elif system.is_debian():
            package_manager = "apt-get"
            args = " -y install"
        elif system.is_fedora():
            package_manager = "yum"
            args = " install"
        elif system.is_arch():
            package_manager = "pacman"
            args = " --noconfirm -S"
        if lib.which(package_manager) is None:
            self.logger.warn("Package manager %s not installed! Packages will not be installed."
                             % package_manager)
            self.package_manager = None
        self.package_manager = package_manager
        self.sudo_required = sudo_required
        self.args = args