Analysis of error handling examples in Go language

package main
import (
    "fmt"
    "time"
)
type MyError struct {
    When
    What string
}
func (e *MyError) Error() string {
    return ("at %v, %s",
        , )
}
func run() error {
    return &MyError{
        (),
        "it didn't work",
    }
}
func main() {
    if err := run(); err != nil {
        (err)
    }
}