title: Get Element Attribute in robot framework
body: <p>hi how to use Get Element Attribute in Robot framework? in instruction I have 
  Return value of element attribute.</p>
  
  <p>attribute_locator consists of element locator followed by an @ sign and attribute name, for example <code>element_id@class</code>.</p>
  
  <p>I have this <code>xpath=${check_radio_xpath}@class</code> is this right way?
  where <code>${check_radio_xpath} =  md-radio-11</code></p>
  
  <p>I get this error:  </p>
  
  <pre><code>${ischecked} = Selenium2Library . Get Element Attribute xpath=${check_radio_xpath}@class
  
  Documentation:
  Return value of element attribute.
  
  TRACE   Arguments: [ 'xpath=md-radio-11@class' ]        
  DEBUG   Finished Request    
  FAIL    ValueError: Element 'xpath=md-radio-11' not found.
  </code></pre>