code: public function hasRequiredValue($postVars, $keys)
      {
          foreach ($keys as $key) {
              $requiredKey = $this->findKey($key, $postVars);
              if (array_key_exists($requiredKey, $postVars) && $postVars[$requiredKey] !== '') return true;
          }
  
          return false;
      }
docs: Since a required field can have multiple possible inputs, this method just checks the
  field has a value and returns true if it does.  If it finds no values in any of the inputs
  it returns false.
  
  @params  Array   $postVars   Greenhouse post parameters.
  @params  Array   $keys       The keys to check for in $postVars
  @return  boolean