def transform_dn_components_to_str(dn_list):
    """ [('DC', 'ch'), ('DC', 'cern'), ('OU', 'computers'), ('CN', 'lhcbci-cernvm03.cern.ch')]
        to /DC=ch/DC=cern/OU=computers/CN=lhcbci-cernvm03.cern.ch"""
    for element in dn_list:
        if len(element) != 2:
            raise ValueError('There must be only 2 elements in this tuple')
    transformed = ['/'+element[0]+'='+element[1] for element in dn_list]
    return ''.join(transformed)