docs: function registerSchema(schema) {
          var typename = getTypenameFromSchemaID(schema.id);
          var registered_schema = tv4.getSchema(schema.id);
          if (registered_schema == null) {
              var is_draft_schema = (schema.id === exports.DRAFT_SCHEMA_ID);
              if (!is_draft_schema) {
                  if (typename == null) {
                      // error typename not available from id
                      return false;
                  }
              }
              else {
                  typename = exports.DRAFT_SCHEMA_TYPENAME;
              }
              var result = tv4_validateSchema(schema);
              if (result.errors.length === 0) {
                  // some docs indicate addSchema() returns boolean, but the source code returns nothing
                  tv4.addSchema(schema);
                  schemas[typename] = schema;
                  return true;
              }
              else {
                  return false;
              }
          }
          else {
              // schema is already registered, don't re-register
              return true;
          }
      }