code: func (pa permAttr) get(attr string) string {
  	if pa.attrs != nil {
  		v := pa.attrs[attr]
  		if len(v) != 0 {
  			return v[0]
  		}
  		return ""
  	}
  
  	if pa.claims != nil {
  		return claimsIntfAttrValue(pa.claims, attr, pa.at, pa.signerFilter)
  	}
  
  	return ""
  }
docs: // get returns the value of attr.