code: public void setNameValueColumnMappings(final Map<String, ?> nameValueColumnMap) {
          if (nameValueColumnMap == null) {
              this.nameValueColumnMappings = null;
          } else {
              final Map<String, Set<String>> mappings = MultivaluedPersonAttributeUtils.parseAttributeToAttributeMapping(nameValueColumnMap);
  
              if (mappings.containsValue(null)) {
                  throw new IllegalArgumentException("nameValueColumnMap may not have null values");
              }
              
              this.nameValueColumnMappings = mappings;
          }
      }
docs: The {@link Map} of columns from a name column to value columns. Keys are Strings,
  Values are Strings or {@link java.util.List} of Strings.
  
  @param nameValueColumnMap The Map of name column to value column(s).