3 files changed, 4 insertions, 0 deletions
diff --git a/stdnum/be/bis.py b/stdnum/be/bis.py
index 77876fe..fc59cf5 100644
--- a/stdnum/be/bis.py
+++ b/stdnum/be/bis.py
@@ -123,3 +123,4 @@ def get_gender(number):
     number = compact(number)
     if int(number[2:4]) >= 40:
         return nn.get_gender(number)
+    return None
diff --git a/stdnum/be/nn.py b/stdnum/be/nn.py
index 135d883..6cf64af 100644
--- a/stdnum/be/nn.py
+++ b/stdnum/be/nn.py
@@ -184,6 +184,7 @@ def get_birth_date(number):
     year, month, day = _get_birth_date_parts(compact(number))
     if year and month and day:
         return datetime.date(year, month, day)
+    return None
 
 
 def get_gender(number):
diff --git a/stdnum/be/ssn.py b/stdnum/be/ssn.py
index 65045c1..e22cfd8 100644
--- a/stdnum/be/ssn.py
+++ b/stdnum/be/ssn.py
@@ -126,6 +126,7 @@ def guess_type(number):
     for mod in _ssn_modules:
         if mod.is_valid(number):
             return mod.__name__.rsplit('.', 1)[-1]
+    return None
 
 
 def format(number):
@@ -153,3 +154,4 @@ def get_gender(number):
     for mod in _ssn_modules:
         if mod.is_valid(number):
             return mod.get_gender(number)
+    return None