In Banner Entertainment, Inc. v. Superior Court (1998) 62 Cal.App.4th 348, the court explained, "it is not the presence or absence of a signature on an agreement which is dispositive; it is the presence or absence of evidence of an agreement to arbitrate which matters." (Id. at p. 361.) Evidence confirming the existence of an agreement to arbitrate, despite an unsigned agreement, can be based, for example, on "conduct from which one could imply either ratification or implied acceptance of such a provision." (Ibid.)