title: Is there any negation logics for expressions in ballerina?
body: <p>I want to know whether it is possible to negate the expression in ballerina like </p>
  
  <blockquote>
    <p>(not expression)</p>
  </blockquote>
  
  <p>or </p>
  
  <blockquote>
    <p>(!expression)</p>
  </blockquote>