original_string: public function getPreviousSibling()
  	{
  		$previous = null;
  		
  		// if this element has an index
  		if (false !== ($index = $this->getIndex())) {
  			// if this element has a previous sibling
  			if ($this->parent->hasChild($index - 1)) {
  				$previous = $this->parent->getChild($index - 1);
  			}
  		}
  		
  		return $previous;
  	}
code: public function getPreviousSibling()
  	{
  		$previous = null;
  		
  		// if this element has an index
  		if (false !== ($index = $this->getIndex())) {
  			// if this element has a previous sibling
  			if ($this->parent->hasChild($index - 1)) {
  				$previous = $this->parent->getChild($index - 1);
  			}
  		}
  		
  		return $previous;
  	}
code_tokens: public function getPreviousSibling ( ) { $ previous = null ; // if this element has an index if ( false !== ( $ index = $ this -> getIndex ( ) ) ) { // if this element has a previous sibling if ( $ this -> parent -> hasChild ( $ index - 1 ) ) { $ previous = $ this -> parent -> getChild ( $ index - 1 ) ; } } return $ previous ; }
docstring: Returns this element's previous sibling or null if no sibling exists
  
  @return  Jstewmc\Rtf\Element\Element|null
  @throws  BadMethodCallException  if the element doesn't have a parent
  @throws  BadMethodCallException  if the element's parent doesn't have children
  @throws  BadMethodCallException  if the element is not a child of its parent
  @since  0.1.0
docstring_tokens: Returns this element s previous sibling or null if no sibling exists