code: func (sp *ServiceProvider) GetSSOBindingLocation(binding string) string {
  	for _, singleSignOnService := range sp.IDPMetadata.IDPSSODescriptor.SingleSignOnService {
  		if singleSignOnService.Binding == binding {
  			return singleSignOnService.Location
  		}
  	}
  	return ""
  }
docs: // GetSSOBindingLocation returns URL for the IDP's Single Sign On Service binding
  // of the specified type (HTTPRedirectBinding or HTTPPostBinding)