<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def verify_signature(message, key, signature):
 """ This function will verify the authenticity of a digital signature. For security purposes, Nylas includes a digital signature in the headers of every webhook notification, so that clients can verify that the webhook request came from Nylas and no one else. The signing key is your OAuth client secret, which only you and Nylas know. """

    digest = hmac.new(key, msg=message, digestmod=hashlib.sha256).hexdigest()
    return digest == signature