Check value against problem and return it unchanged when it is valid. Otherwise throw an OparlValidationError reading Invalid <name>: <reason>. Inside an async method the throw becomes a rejection, before any request is made.
value
problem
Invalid <name>: <reason>
async
Check
valueagainstproblemand return it unchanged when it is valid. Otherwise throw an OparlValidationError readingInvalid <name>: <reason>. Inside anasyncmethod the throw becomes a rejection, before any request is made.