def cmr_url_for_env(which_cmr):
    """ Return the environment specific URL for CMR """
    cmrs = {'sit':'https://cmr.sit.earthdata.nasa.gov',
        'uat':'https://cmr.uat.earthdata.nasa.gov',
        'ops':'https://cmr.earthdata.nasa.gov',
        'prod':'https://cmr.earthdata.nasa.gov'}
    return cmrs.get(which_cmr, 'https://cmr.earthdata.nasa.gov')