anchor.diff:  %% Function: parse_register_contact_expire(Header, Contact)
   %%           parse_register_contact_expire(ExpireHeader, Contact)
   %%           Header  = keylist record(), the request headers
  -%%           ExpireHeader = sipheader:expire(Header) return value
  +%%           ExpireHeader = sipheader:expires(Header) return value
   %%           Contact = contact record(), a contact entry from a request
   %% Descrip.: determine the expire time supplied for a contact in a SIP
   %%           REGISTER request
  
positive.code: %% - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
  %% there is only one Contact and it's a wildcard
  is_valid_wildcard_request(Header, [ #contact{urlstr = "*"} ]) ->
      case sipheader:expire(Header) of
  	[Expire] ->
  	    %% cast to integer so that "0", "00" ... and so on are all considered as 0
  	    case catch list_to_integer(Expire) of
  
negative.code: 
  parse_register_contact_expire(Header, Contact) when is_record(Header, keylist),
  						    is_record(Contact, contact) ->
      ExpireHeader = sipheader:expires(Header),
      parse_register_contact_expire(ExpireHeader, Contact).
  
      
  