'Updates the metadata document for an existing SAML provider.
This operation requires `Signature Version 4`_.
:type saml_provider_arn: string
:param saml_provider_arn: The Amazon Resource Name (ARN) of the SAML
provider to update.
:type saml_metadata_document: string
:param saml_metadata_document: An XML document generated by an identity
provider (IdP) that supports SAML 2.0. The document includes the
issuer\'s name, expiration information, and keys that can be used to
validate the SAML authentication response (assertions) that are
received from the IdP. You must generate the metadata document
using the identity management software that is used as your
organization\'s IdP.'

def update_saml_provider(self, saml_provider_arn, saml_metadata_document):

    params = {'SAMLMetadataDocument': saml_metadata_document, 'SAMLProviderArn': saml_provider_arn}
    return self.get_response('UpdateSAMLProvider', params)
