refactor exeption name

exceptions.py

@@ -20,5 +20,5 @@ class SequenceMissingError(ValidationError):
     pass
 
 
-class MemberUnpaiedFeeError(ValidationError):
+class MemberUnpaidFeeError(ValidationError):
     pass

member.py

@@ -8,7 +8,7 @@ from trytond.pool import Pool
 from trytond.i18n import gettext
 from trytond.wizard import Wizard, StateView, Button, StateReport
 from trytond.report import Report
-from .exceptions import MemberUnpaiedFeeError
+from .exceptions import MemberUnpaidFeeError
 
 __all__ = [
     'Member', 'MembersBookWizard', 'PrintMembersBookStart', 'MembersBookReport'
@@ -197,7 +197,7 @@ class Member(Workflow, ModelSQL, ModelView):
         pending_fees = Fee.search([('member', 'in', members)])
 
         if not all(x.paid for x in pending_fees):
-            raise MemberUnpaiedFeeError(
+            raise MemberUnpaidFeeError(
                 gettext('association.msg_unpaid_fee',
                         member=", ".join([x.party_name for x in members])))