code: public NameOpValue removeParam(String attribute) {
          if (_relations == null || attribute == null) return null;
  
          Iterator iter = _relations.iterator();
          NameOpValue nv;
  	String canonAttrib = canonicalize(attribute);
          String tmpCanonAttrib = null;
          while(iter.hasNext()) {
              nv = (NameOpValue)iter.next();
              tmpCanonAttrib = canonicalize(nv.getAttribute());
              if (tmpCanonAttrib.equalsIgnoreCase(canonAttrib)) {
  		iter.remove();
                  return nv;
              }
          }
          return null;
      }
docs: Removes a relation for the specified attribute.
  
  @param attribute the attribute name for the
  relation to remove.
  @return the relation that was removed.