How to use the fbjs/lib/emptyFunction.thatReturnsArgument function in fbjs

function mapSingleChildIntoContext(bookKeeping, child, childKey) {
  var result = bookKeeping.result;
  var keyPrefix = bookKeeping.keyPrefix;
  var func = bookKeeping.func;
  var context = bookKeeping.context;

  var mappedChild = func.call(context, child, bookKeeping.count++);
  if (Array.isArray(mappedChild)) {
    mapIntoWithKeyPrefixInternal(
      mappedChild,
      result,
      childKey,
      emptyFunction.thatReturnsArgument
    );
  } else if (mappedChild != null) {
    if (React.isValidElement(mappedChild)) {
      mappedChild = cloneAndReplaceKey(
        mappedChild,
        // Keep both the (mapped) and old keys if they differ, just as
        // traverseAllChildren used to do for objects as children
        keyPrefix +
          (mappedChild.key && (!child || child.key !== mappedChild.key)
            ? escapeUserProvidedKey(mappedChild.key) + '/'
            : '') +
          childKey
      );
    }
    result.push(mappedChild);
  }

function mapSingleChildIntoContext(bookKeeping, child, childKey) {
  var result = bookKeeping.result;
  var keyPrefix = bookKeeping.keyPrefix;
  var func = bookKeeping.func;
  var context = bookKeeping.context;

  var mappedChild = func.call(context, child, bookKeeping.count++);
  if (Array.isArray(mappedChild)) {
    mapIntoWithKeyPrefixInternal(
      mappedChild,
      result,
      childKey,
      emptyFunction.thatReturnsArgument
    );
  } else if (mappedChild != null) {
    if (React.isValidElement(mappedChild)) {
      mappedChild = cloneAndReplaceKey(
        mappedChild,
        // Keep both the (mapped) and old keys if they differ, just as
        // traverseAllChildren used to do for objects as children
        keyPrefix +
          (mappedChild.key && (!child || child.key !== mappedChild.key)
            ? escapeUserProvidedKey(mappedChild.key) + '/'
            : '') +
          childKey
      );
    }
    result.push(mappedChild);
  }

process.env.NODE_ENV !== 'production' ? warning(false, 'React.addons.createFragment does not accept a ReactElement ' + 'without a wrapper object.') : void 0;
      return object;
    }

    !(object.nodeType !== 1) ? process.env.NODE_ENV !== 'production' ? invariant(false, 'React.addons.createFragment(...): Encountered an invalid child; DOM elements are not valid children of React components.') : _prodInvariant('0') : void 0;

    var result = [];

    for (var key in object) {
      if (process.env.NODE_ENV !== 'production') {
        if (!warnedAboutNumeric && numericPropertyRegex.test(key)) {
          process.env.NODE_ENV !== 'production' ? warning(false, 'React.addons.createFragment(...): Child objects should have ' + 'non-numeric keys so ordering is preserved.') : void 0;
          warnedAboutNumeric = true;
        }
      }
      ReactChildren.mapIntoWithKeyPrefixInternal(object[key], result, key, emptyFunction.thatReturnsArgument);
    }

    return result;
  }
};

process.env.NODE_ENV !== 'production' ? warning(false, 'React.addons.createFragment does not accept a ReactElement ' + 'without a wrapper object.') : undefined;
      return object;
    }

    !(object.nodeType !== 1) ? process.env.NODE_ENV !== 'production' ? invariant(false, 'React.addons.createFragment(...): Encountered an invalid child; DOM ' + 'elements are not valid children of React components.') : invariant(false) : undefined;

    var result = [];

    for (var key in object) {
      if (process.env.NODE_ENV !== 'production') {
        if (!warnedAboutNumeric && numericPropertyRegex.test(key)) {
          process.env.NODE_ENV !== 'production' ? warning(false, 'React.addons.createFragment(...): Child objects should have ' + 'non-numeric keys so ordering is preserved.') : undefined;
          warnedAboutNumeric = true;
        }
      }
      ReactChildren.mapIntoWithKeyPrefixInternal(object[key], result, key, emptyFunction.thatReturnsArgument);
    }

    return result;
  }
};

for (var key in object) {
      if (__DEV__) {
        if (!warnedAboutNumeric && numericPropertyRegex.test(key)) {
          warning(
            false,
            'React.addons.createFragment(...): Child objects should have ' +
              'non-numeric keys so ordering is preserved.',
          );
          warnedAboutNumeric = true;
        }
      }
      ReactChildren.mapIntoWithKeyPrefixInternal(
        object[key],
        result,
        key,
        emptyFunction.thatReturnsArgument,
      );
    }

    return result;
  },
};

getDefaultProps: function () {
    return {
      component: 'span',
      childFactory: emptyFunction.thatReturnsArgument
    };
  },

function toArray(children) {
  var result = [];
  mapIntoWithKeyPrefixInternal(children, result, null, emptyFunction.thatReturnsArgument);
  return result;
}

function toArray(children) {
  var result = [];
  mapIntoWithKeyPrefixInternal(children, result, null, emptyFunction.thatReturnsArgument);
  return result;
}

getDefaultProps: function () {
    return {
      component: 'span',
      childFactory: emptyFunction.thatReturnsArgument
    };
  },

function toArray(children) {
      var result = [];
      mapIntoWithKeyPrefixInternal(
        children,
        result,
        null,
        emptyFunction.thatReturnsArgument
      );
      return result;
    }