+Generally, 'state' alone will return an array of area codes or region names
+in the state.
+
+'state' and 'areacode' together will return an array of exchanges (NXX
+prefixes), or for some exports, an array of ratecenter names.
+
+'areacode' and 'exchange', or 'state' and 'ratecenter', or 'region' by itself
+will return an array of actual DID numbers.
+
+Passing 'tollfree' with a true value will override the whole hierarchy and
+return an array of tollfree numbers.
+
+=cut
+
+# no stub; can('get_dids') should return false by default
+
+#default fallbacks... FS::part_export::DID_Common ?
+sub can_get_dids { 0; }
+sub get_dids_can_tollfree { 0; }
+sub get_dids_can_manual { 0; }
+sub get_dids_can_edit { 0; } #don't use without can_manual, otherwise the
+ # DID selector provisions a new number from
+ # inventory each edit
+sub get_dids_npa_select { 1; }
+
+# get_dids_npa_select: if true, then prompt to select state, then area code,
+# then city/exchange, then phone number.
+# if false, then prompt to select state (actually province), then "region",
+# then phone number.
+#
+# get_dids_can_manual: if true, then there will be a radio button to enter
+# a phone number manually.
+#
+# get_dids_can_tollfree: if true, then the user will be prompted to choose
+# both a regular and a toll-free number. The export can have a
+# 'restrict_selection' option to enable only one or the other of those. See
+# part_export/vitelity.pm for an example.
+#
+# get_dids_can_edit: if true, then the user can use the selector again to
+# change the phone number for a service. if false, then they can't (have to
+# reprovision completely).
+
+=item svc_role SVC
+
+Returns the role that SVC occupies with respect to this export, if any.
+This is part of the part_svc's export configuration.