diff --git a/.github/workflows/python.yml b/.github/workflows/python.yml
index e6e0074..19c693e 100644
--- a/.github/workflows/python.yml
+++ b/.github/workflows/python.yml
@@ -20,7 +20,7 @@ jobs:
       - name: Install dependencies
         run: |
           python -m pip install --upgrade pip
-          python -m pip install flake8 flake8-import-order
+          python -m pip install flake8==5.0.4 flake8-import-order
 
       - name: Lint with flake8
         run: |
diff --git a/moai/metadata/datacite.py b/moai/metadata/datacite.py
index 3f8ee48..d1bba2b 100644
--- a/moai/metadata/datacite.py
+++ b/moai/metadata/datacite.py
@@ -89,9 +89,11 @@ def __call__(self, element, metadata):
                 if not isinstance(idf_list, list):
                     idf_list = [idf_list]
                 for identifier in idf_list:
-                    nameIdf = NONE.nameIdentifier(identifier['Name_Identifier'])
-                    nameIdf.attrib['nameIdentifierScheme'] = identifier['Name_Identifier_Scheme']
-                    creator.append(nameIdf)
+                    if 'Name_Identifier' in identifier:
+                        nameIdf = NONE.nameIdentifier(identifier['Name_Identifier'])
+                        if 'Name_Identifier_Scheme' in identifier:
+                            nameIdf.attrib['nameIdentifierScheme'] = identifier['Name_Identifier_Scheme']
+                        creator.append(nameIdf)
 
                 creators.append(creator)
             datacite.append(creators)
@@ -214,9 +216,11 @@ def __call__(self, element, metadata):
                 if not isinstance(idf_list, list):
                     idf_list = [idf_list]
                 for identifier in idf_list:
-                    nameIdf = NONE.nameIdentifier(identifier['Name_Identifier'])
-                    nameIdf.attrib['nameIdentifierScheme'] = identifier['Name_Identifier_Scheme']
-                    contributor.append(nameIdf)
+                    if 'Name_Identifier' in identifier:
+                        nameIdf = NONE.nameIdentifier(identifier['Name_Identifier'])
+                        if 'Name_Identifier_Scheme' in identifier:
+                            nameIdf.attrib['nameIdentifierScheme'] = identifier['Name_Identifier_Scheme']
+                        contributor.append(nameIdf)
 
                 contributors.append(contributor)
 
@@ -242,9 +246,12 @@ def __call__(self, element, metadata):
                     if not isinstance(idf_list, list):
                         idf_list = [idf_list]
                     for identifier in idf_list:
-                        nameIdf = NONE.nameIdentifier(identifier['Name_Identifier'])
-                        nameIdf.attrib['nameIdentifierScheme'] = identifier['Name_Identifier_Scheme']
-                        contributor.append(nameIdf)
+
+                        if 'Name_Identifier' in identifier:
+                            nameIdf = NONE.nameIdentifier(identifier['Name_Identifier'])
+                            if 'Name_Identifier_Scheme' in identifier:
+                                nameIdf.attrib['nameIdentifierScheme'] = identifier['Name_Identifier_Scheme']
+                            contributor.append(nameIdf)
 
                     contributors.append(contributor)
             except KeyError:
diff --git a/moai/metadata/oaidc.py b/moai/metadata/oaidc.py
index 87e7231..68b637c 100644
--- a/moai/metadata/oaidc.py
+++ b/moai/metadata/oaidc.py
@@ -137,7 +137,7 @@ def __call__(self, element, metadata):
             if not isinstance(con_list, list):
                 con_list = [con_list]
 
-            for dccon in creator_list:
+            for dccon in con_list:
                 name = dccon['Name']['Given_Name'] + ' ' + dccon['Name']['Family_Name']
 
                 affiliation_list = dccon['Affiliation']