code: function splitKeys (keys) {
  		if (typeof(keys) === 'string') {
  			return keys.replace(/^\s*\.\s*/,'')
  				.replace(/(?:\s*\.\s*)+/g, '.')
  				.split('.');
  		}
  		else if (Array.isArray(keys)) {
  			return [].concat(keys);
  		}
  		return;
  	}
docs: Normalize and split `keys` for `get` and `set` method.
  Splits by "."
  
  @param {String|Array} keys
  @api private