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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 install_yum_priorities(distro, _yum=None):
 """ EPEL started packaging Ceph so we need to make sure that the ceph.repo we install has a higher priority than the EPEL repo so that when installing Ceph it will come from the repo file we create. The name of the package changed back and forth (!) since CentOS 4: From the CentOS wiki:: Note: This plugin has carried at least two differing names over time. It is named yum-priorities on CentOS-5 but was named yum-plugin-priorities on CentOS-4. CentOS-6 has reverted to yum-plugin-priorities. :params _yum: Used for testing, so we can inject a fake yum """

    yum = _yum or pkg_managers.yum
    package_name = 'yum-plugin-priorities'

    if distro.normalized_name == 'centos':
        if distro.release[0] != '6':
            package_name = 'yum-priorities'
    yum(distro.conn, package_name)