diff --git a/ldapserver/exceptions.py b/ldapserver/exceptions.py
index 69a45dfb8b4cf87bda8063cf02edc07151bb2e90..109e310e9bdef75e1308e4d6b11eb248b04805fa 100644
--- a/ldapserver/exceptions.py
+++ b/ldapserver/exceptions.py
@@ -3,126 +3,126 @@ from .ldap import LDAPResultCode
 class LDAPError(Exception):
 	'''Base class for all LDAP errors'''
 
-	result_code = None
+	RESULT_CODE: LDAPResultCode
 
 	def __init__(self, message=''):
 		super().__init__()
-		self.code = self.result_code
+		self.code = self.RESULT_CODE
 		self.message = message
 
 #class LDAPSuccess(LDAPError):
-#	result_code = LDAPResultCode.success
+#	RESULT_CODE = LDAPResultCode.success
 
 class LDAPOperationsError(LDAPError):
-	result_code = LDAPResultCode.operationsError
+	RESULT_CODE = LDAPResultCode.operationsError
 
 class LDAPProtocolError(LDAPError):
-	result_code = LDAPResultCode.protocolError
+	RESULT_CODE = LDAPResultCode.protocolError
 
 class LDAPTimeLimitExceeded(LDAPError):
-	result_code = LDAPResultCode.timeLimitExceeded
+	RESULT_CODE = LDAPResultCode.timeLimitExceeded
 
 class LDAPSizeLimitExceeded(LDAPError):
-	result_code = LDAPResultCode.sizeLimitExceeded
+	RESULT_CODE = LDAPResultCode.sizeLimitExceeded
 
 #class LDAPCompareFalse(LDAPError):
-#	result_code = LDAPResultCode.compareFalse
+#	RESULT_CODE = LDAPResultCode.compareFalse
 
 #class LDAPCompareTrue(LDAPError):
-#	result_code = LDAPResultCode.compareTrue
+#	RESULT_CODE = LDAPResultCode.compareTrue
 
 class LDAPAuthMethodNotSupported(LDAPError):
-	result_code = LDAPResultCode.authMethodNotSupported
+	RESULT_CODE = LDAPResultCode.authMethodNotSupported
 
 class LDAPStrongerAuthRequired(LDAPError):
-	result_code = LDAPResultCode.strongerAuthRequired
+	RESULT_CODE = LDAPResultCode.strongerAuthRequired
 
 #class LDAPReferral(LDAPError):
-#	result_code = LDAPResultCode.referral
+#	RESULT_CODE = LDAPResultCode.referral
 
 class LDAPAdminLimitExceeded(LDAPError):
-	result_code = LDAPResultCode.adminLimitExceeded
+	RESULT_CODE = LDAPResultCode.adminLimitExceeded
 
 class LDAPUnavailableCriticalExtension(LDAPError):
-	result_code = LDAPResultCode.unavailableCriticalExtension
+	RESULT_CODE = LDAPResultCode.unavailableCriticalExtension
 
 class LDAPConfidentialityRequired(LDAPError):
-	result_code = LDAPResultCode.confidentialityRequired
+	RESULT_CODE = LDAPResultCode.confidentialityRequired
 
 #class LDAPSaslBindInProgress(LDAPError):
-#	result_code = LDAPResultCode.saslBindInProgress
+#	RESULT_CODE = LDAPResultCode.saslBindInProgress
 
 class LDAPNoSuchAttribute(LDAPError):
-	result_code = LDAPResultCode.noSuchAttribute
+	RESULT_CODE = LDAPResultCode.noSuchAttribute
 
 class LDAPUndefinedAttributeType(LDAPError):
-	result_code = LDAPResultCode.undefinedAttributeType
+	RESULT_CODE = LDAPResultCode.undefinedAttributeType
 
 class LDAPInappropriateMatching(LDAPError):
-	result_code = LDAPResultCode.inappropriateMatching
+	RESULT_CODE = LDAPResultCode.inappropriateMatching
 
 class LDAPConstraintViolation(LDAPError):
-	result_code = LDAPResultCode.constraintViolation
+	RESULT_CODE = LDAPResultCode.constraintViolation
 
 class LDAPAttributeOrValueExists(LDAPError):
-	result_code = LDAPResultCode.attributeOrValueExists
+	RESULT_CODE = LDAPResultCode.attributeOrValueExists
 
 class LDAPInvalidAttributeSyntax(LDAPError):
-	result_code = LDAPResultCode.invalidAttributeSyntax
+	RESULT_CODE = LDAPResultCode.invalidAttributeSyntax
 
 class LDAPNoSuchObject(LDAPError):
-	result_code = LDAPResultCode.noSuchObject
+	RESULT_CODE = LDAPResultCode.noSuchObject
 
 class LDAPAliasProblem(LDAPError):
-	result_code = LDAPResultCode.aliasProblem
+	RESULT_CODE = LDAPResultCode.aliasProblem
 
 class LDAPInvalidDNSyntax(LDAPError):
-	result_code = LDAPResultCode.invalidDNSyntax
+	RESULT_CODE = LDAPResultCode.invalidDNSyntax
 
 class LDAPAliasDereferencingProblem(LDAPError):
-	result_code = LDAPResultCode.aliasDereferencingProblem
+	RESULT_CODE = LDAPResultCode.aliasDereferencingProblem
 
 class LDAPInappropriateAuthentication(LDAPError):
-	result_code = LDAPResultCode.inappropriateAuthentication
+	RESULT_CODE = LDAPResultCode.inappropriateAuthentication
 
 class LDAPInvalidCredentials(LDAPError):
-	result_code = LDAPResultCode.invalidCredentials
+	RESULT_CODE = LDAPResultCode.invalidCredentials
 
 class LDAPInsufficientAccessRights(LDAPError):
-	result_code = LDAPResultCode.insufficientAccessRights
+	RESULT_CODE = LDAPResultCode.insufficientAccessRights
 
 class LDAPBusy(LDAPError):
-	result_code = LDAPResultCode.busy
+	RESULT_CODE = LDAPResultCode.busy
 
 class LDAPUnavailable(LDAPError):
-	result_code = LDAPResultCode.unavailable
+	RESULT_CODE = LDAPResultCode.unavailable
 
 class LDAPUnwillingToPerform(LDAPError):
-	result_code = LDAPResultCode.unwillingToPerform
+	RESULT_CODE = LDAPResultCode.unwillingToPerform
 
 class LDAPLoopDetect(LDAPError):
-	result_code = LDAPResultCode.loopDetect
+	RESULT_CODE = LDAPResultCode.loopDetect
 
 class LDAPNamingViolation(LDAPError):
-	result_code = LDAPResultCode.namingViolation
+	RESULT_CODE = LDAPResultCode.namingViolation
 
 class LDAPObjectClassViolation(LDAPError):
-	result_code = LDAPResultCode.objectClassViolation
+	RESULT_CODE = LDAPResultCode.objectClassViolation
 
 class LDAPNotAllowedOnNonLeaf(LDAPError):
-	result_code = LDAPResultCode.notAllowedOnNonLeaf
+	RESULT_CODE = LDAPResultCode.notAllowedOnNonLeaf
 
 class LDAPNotAllowedOnRDN(LDAPError):
-	result_code = LDAPResultCode.notAllowedOnRDN
+	RESULT_CODE = LDAPResultCode.notAllowedOnRDN
 
 class LDAPEntryAlreadyExists(LDAPError):
-	result_code = LDAPResultCode.entryAlreadyExists
+	RESULT_CODE = LDAPResultCode.entryAlreadyExists
 
 class LDAPObjectClassModsProhibited(LDAPError):
-	result_code = LDAPResultCode.objectClassModsProhibited
+	RESULT_CODE = LDAPResultCode.objectClassModsProhibited
 
 class LDAPAffectsMultipleDSAs(LDAPError):
-	result_code = LDAPResultCode.affectsMultipleDSAs
+	RESULT_CODE = LDAPResultCode.affectsMultipleDSAs
 
 class LDAPOther(LDAPError):
-	result_code = LDAPResultCode.other
+	RESULT_CODE = LDAPResultCode.other