| context | Package context defines the Context type, which carries deadlines, cancellation signals, and other request-scoped values across API boundaries and between processes. |
| errors | Package errors implements functions to manipulate errors. |
| fmt | Package fmt implements formatted I/O with functions analogous to C's printf and scanf. |
| golang.org/x/oauth2/google | Package google provides support for making OAuth2 authorized and authenticated HTTP requests to Google APIs. |
| google.golang.org/api/option | |
| google.golang.org/api/transport | |
| os | Package os provides a platform-independent interface to operating system functionality. |