docs: def resolve(self, ref, document=None):
          """Resolve a ref within the schema.
  
          This is just a convenience method, since RefResolver returns both a URI
          and the resolved value, and we usually just need the resolved value.
  
          :param str ref: URI to resolve.
          :param dict document: Optional schema in which to resolve the URI.
          :returns: the portion of the schema that the URI references.
          :see: :meth:`SchemaRefResolver.resolve`
          """
          _, resolved = self.resolver.resolve(ref, document=document)
          return resolved