def METHOD_NAME(self, tymth, tock=0.0):
    """ Check for any credential messages in mailboxes and list all held credentials
    Parameters:
        tymth (function): injected function wrapper closure returned by .tymen() of
            Tymist instance. Calling tymth() returns associated Tymist .tyme.
        tock (float): injected initial tock value
    Returns:  doifiable Doist compatible generator method
    """
    # enter context
    self.wind(tymth)
    self.tock = tock
    _ = (yield self.tock)
    if self.poll:
        end = helping.nowUTC() + datetime.timedelta(seconds=5)
        sys.stdout.write(f"Checking mailboxes for any {'issued' if self.issued else 'received'} credentials")
        sys.stdout.flush()
        while helping.nowUTC() < end:
            sys.stdout.write(".")
            sys.stdout.flush()
            if "/credential" in self.mbx.times:
                end = self.mbx.times['/credential'] + datetime.timedelta(seconds=5)
            yield 1.0
        print("\n")
    if self.issued:
        saids = self.rgy.reger.issus.get(keys=self.hab.pre)
    else:
        saids = self.rgy.reger.subjs.get(keys=self.hab.pre)
    if self.schema is not None:
        scads = self.rgy.reger.schms.get(keys=self.schema)
        saids = [saider for saider in saids if saider.qb64 in [saider.qb64 for saider in scads]]
    if self.said:
        for said in saids:
            print(said.qb64)
    else:
        print(f"Current {'issued' if self.issued else 'received'} credentials for {self.hab.name} ({self.hab.pre}):\n")
        creds = self.rgy.reger.cloneCreds(saids)
        for idx, cred in enumerate(creds):
            sad = cred['sad']
            status = cred["status"]
            schema = sad['s']
            scraw = self.mbx.verifier.resolver.resolve(schema)
            if not scraw:
                raise kering.ConfigurationError("Credential schema {} not found".format(schema))
            schemer = scheming.Schemer(raw=scraw)
            print(f"Credential #{idx+1}: {sad['d']}")
            print(f"    Type: {schemer.sed['title']}")
            if status['et'] == 'iss' or status['et'] == 'bis':
                print(f"    Status: Issued {terming.Colors.OKGREEN}{terming.Symbols.CHECKMARK}{terming.Colors.ENDC}")
            elif status['et'] == 'rev' or status['et'] == 'brv':
                print(f"    Status: Revoked {terming.Colors.FAIL}{terming.Symbols.FAILED}{terming.Colors.ENDC}")
            else:
                print(f"    Status: Unknown")
            print(f"    Issued by {sad['i']}")
            print(f"    Issued on {status['dt']}")
            if self.verbose:
                bsad = json.dumps(sad, indent=2)
                print("    Full Credential:")
                for line in bsad.splitlines():
                    print(f"\t{line}")
    self.remove([self.mbx])