diff --git a/kibot/var_base.py b/kibot/var_base.py
index c653be57..31eaaacd 100644
--- a/kibot/var_base.py
+++ b/kibot/var_base.py
@@ -40,7 +40,7 @@ class BaseVariant(RegVariant):
                 Use '_kibom_dnc' for the default KiBoM behavior """
 
     def get_variant_field(self):
-        ''' Returns the name of the field used to determine if the component belongs to the variant '''
+        """ Returns the name of the field used to determine if the component belongs to the variant """
         return None
 
     def filter(self, comps):
diff --git a/kibot/var_ibom.py b/kibot/var_ibom.py
index 7445b2a0..c74e241f 100644
--- a/kibot/var_ibom.py
+++ b/kibot/var_ibom.py
@@ -33,7 +33,7 @@ class IBoM(BaseVariant):  # noqa: F821
             """ [string|list(string)=''] List of board variants to include in the BOM """
 
     def get_variant_field(self):
-        ''' Returns the name of the field used to determine if the component belongs to the variant '''
+        """ Returns the name of the field used to determine if the component belongs to the variant """
         return self.variant_field
 
     def config(self, parent):
diff --git a/kibot/var_kibom.py b/kibot/var_kibom.py
index 45f0d34a..826a9853 100644
--- a/kibot/var_kibom.py
+++ b/kibot/var_kibom.py
@@ -34,7 +34,7 @@ class KiBoM(BaseVariant):  # noqa: F821
             """ [string|list(string)=''] Board variant(s) """
 
     def get_variant_field(self):
-        ''' Returns the name of the field used to determine if the component belongs to the variant '''
+        """ Returns the name of the field used to determine if the component belongs to the variant """
         return self.config_field
 
     def set_def_filters(self, exclude_filter, dnf_filter, dnc_filter):
diff --git a/kibot/var_kicost.py b/kibot/var_kicost.py
index ac3932ec..d806b806 100644
--- a/kibot/var_kicost.py
+++ b/kibot/var_kicost.py
@@ -39,7 +39,7 @@ class KiCost(BaseVariant):  # noqa: F821
                 Only supported internally, don't use it if you plan to use KiCost """
 
     def get_variant_field(self):
-        ''' Returns the name of the field used to determine if the component belongs to the variant '''
+        """ Returns the name of the field used to determine if the component belongs to the variant """
         return self.variant_field
 
     def config(self, parent):
diff --git a/tests/test_plot/test_kicost.py b/tests/test_plot/test_kicost.py
index 5f7476fb..f0838fe0 100644
--- a/tests/test_plot/test_kicost.py
+++ b/tests/test_plot/test_kicost.py
@@ -53,7 +53,7 @@ def check_simple(ctx, variant):
 
 
 def test_kicost_simple(test_dir):
-    ''' External KiCost using variants, very simple case '''
+    """ External KiCost using variants, very simple case """
     prj = 'kibom-variant_kicost'
     ctx = context.TestContextSCH(test_dir, 'test_kicost_simple', prj, 'kicost_simple', OUT_DIR)
     ctx.run()
@@ -65,7 +65,7 @@ def test_kicost_simple(test_dir):
 
 
 def test_kicost_bom_simple(test_dir):
-    ''' Internal BoM + KiCost, very simple case. With DNF sheet. '''
+    """ Internal BoM + KiCost, very simple case. With DNF sheet. """
     prj = 'kibom-variant_2c'
     ctx = context.TestContextSCH(test_dir, 'test_kicost_bom_simple', prj, 'int_bom_kicost_simple_xlsx', OUT_DIR)
     ctx.run(kicost=True)  # , extra_debug=True
@@ -80,7 +80,7 @@ def test_kicost_bom_simple(test_dir):
 
 
 def test_kicost_bom_sel_dist_1(test_dir):
-    ''' Internal BoM + KiCost, select distributors (Mouser+Digi-Key). With DNF sheet. '''
+    """ Internal BoM + KiCost, select distributors (Mouser+Digi-Key). With DNF sheet. """
     prj = 'kibom-variant_2c'
     ctx = context.TestContextSCH(test_dir, 'test_kicost_bom_sel_dist_1', prj, 'int_bom_kicost_sel_dist_1_xlsx', OUT_DIR)
     ctx.run(kicost=True)  # , extra_debug=True
@@ -95,7 +95,7 @@ def test_kicost_bom_sel_dist_1(test_dir):
 
 
 def test_kicost_bom_merge_1(test_dir):
-    ''' Internal BoM + KiCost, merging 3 projects. '''
+    """ Internal BoM + KiCost, merging 3 projects. """
     prj = 'merge_1'
     yaml = 'int_bom_kicost_merge_xlsx'
     if context.ki6():