ValidateArgCount validates the number of arguments and returns the corresponding error if there are any.

ValidateArgs validates arguments with the given validate.Argument functions.

ValidateTemplate validates the template structure given the template path.

ValidateVarArgs validates variadic arguments with the given validate.Argument function.

InvalidArg error message format string for filling in the details of an invalid arg.

ErrNotEnoughArgs indicates that the given number of arguments does not match the expected number of arguments.

ErrUnexpectedArgs indicates that the given number of arguments exceed the expected number of arguments.