# Functions
ErrorResp sends an error response with the appropriate status code.
GetInvalidCustomError handles GET /invalid-error requests.
GetUsers handles GET /users requests.
Login handles POST /login requests.
NewMissingUserPasswordError creates a new MissingUserPasswordError instance.
# Constants
Error code in category 901xxx (Unauthorized Error).
# Structs
ErrorResponse represents the structure of the error response.
InvalidCustomError is an example error type that does not embed BaseError.
MissingUserPasswordError represents an error when username or password is missing.