func (gsa *GServiceAccount) Client(ctxt context.Context, scopes ...string) (*http.Client, error) {
	b, err := gsa.TokenSource(ctxt, scopes...)
	if err != nil {
		return nil, err
	}
	return b.Client(), nil
}
func (gsa *GServiceAccount) Client(ctxt context.Context, scopes ...string) (*http.Client, error) {
	b, err := gsa.TokenSource(ctxt, scopes...)
	if err != nil {
		return nil, err
	}
	return b.Client(), nil
}
// Client returns a HTTP client using the provided context and scopes for the
// service account as the underlying transport.
//
// When called with the appropriate scopes, the created client can be passed to
// any Google API for creating a service client:
//
// 		import (
// 			dns "google.golang.org/api/dns/v2beta1"
//      )
//      cl, err := gsa.Client(ctxt, dns.CloudPlatformScope, dns.NdevClouddnsReadwriteScope)
// 		if err != nil { /* ... */ }
//      dnsService, err := dns.New(cl)
// 		if err != nil { /* ... */ }
//
// Note: this is a convenience func only.