cdm/src/main/java/ucar/nc2/dataset/CoordSysBuilder.java
static public String buildConventionAttribute(String mainConv, String... convAtts) {
    List<String> result = new ArrayList<>();
    result.add(mainConv);
    for (String convs : convAtts) {
      if (convs == null) continue;
      List<String> ss = breakupConventionNames(convs); // may be a list
      for (String s : ss) {
        if (matchConvention(s) == null)  // only add extra ones, not ones that compete with mainConv
          result.add(s);
      }
    }

    // now form comma separated result
    boolean start = true;
    Formatter f = new Formatter();
    for (String s : result) {
      if (start)
        f.format("%s", s);
      else
        f.format(", %s", s);
      start = false;
    }
    return f.toString();
  }
static public String buildConventionAttribute(String mainConv, String... convAtts) {
    List<String> result = new ArrayList<>();
    result.add(mainConv);
    for (String convs : convAtts) {
      if (convs == null) continue;
      List<String> ss = breakupConventionNames(convs); // may be a list
      for (String s : ss) {
        if (matchConvention(s) == null)  // only add extra ones, not ones that compete with mainConv
          result.add(s);
      }
    }

    // now form comma separated result
    boolean start = true;
    Formatter f = new Formatter();
    for (String s : result) {
      if (start)
        f.format("%s", s);
      else
        f.format(", %s", s);
      start = false;
    }
    return f.toString();
  }
Build a list of Conventions

@param mainConv this is the main convention
@param convAtts list of others, onbly use "extra" Conventions
@return comma separated list of Conventions