'Inserts a new type of ``Credentials`` instance into the chain that will
be tried after an existing one.
:param name: The short name of the credentials you\'d like to insert the
new credentials after. (ex. ``env`` or ``config``). Existing names
& ordering can be discovered via ``self.available_methods``.
:type name: string
:param cred_instance: An instance of the new ``Credentials`` object
you\'d like to add to the chain.
:type cred_instance: A subclass of ``Credentials``'

def insert_after(self, name, credential_provider):

    offset = self._get_provider_offset(name)
    self.providers.insert((offset + 1), credential_provider)
