def create_signed_entities_descriptor(entity_descriptors, security_context, valid_for=None):
    """
    :param entity_descriptors: the entity descriptors to put in in an EntitiesDescriptor tag and sign
    :param security_context: security context for the signature
    :param valid_for: number of hours the metadata should be valid
    :return: the signed XML document

    :type entity_descriptors: Sequence[saml2.md.EntityDescriptor]]
    :type security_context: saml2.sigver.SecurityContext
    :type valid_for: Optional[int]
    """
    entities_desc, xmldoc = entities_descriptor(entity_descriptors, valid_for=valid_for, name=None, ident=None,
                                                sign=True, secc=security_context)
    if not valid_instance(entities_desc):
        raise ValueError("Could not construct valid EntitiesDescriptor tag")

    return xmldoc