code: func (account *Account) ChangePassword(old, new string) error {
  	insta := account.inst
  	data, err := insta.prepareData(
  		map[string]interface{}{
  			"old_password":  old,
  			"new_password1": new,
  			"new_password2": new,
  		},
  	)
  	if err == nil {
  		_, err = insta.sendRequest(
  			&reqOptions{
  				Endpoint: urlChangePass,
  				Query:    generateSignature(data),
  				IsPost:   true,
  			},
  		)
  	}
  	return err
  }
docs: // ChangePassword changes current password.
  //
  // GoInsta does not store current instagram password (for security reasons)
  // If you want to change your password you must parse old and new password.
  //
  // See example: examples/account/changePass.go