diff --git a/parse_powerisa_pdf/parse_powerisa_pdf.py b/parse_powerisa_pdf/parse_powerisa_pdf.py
index 527c5cb..c7187d1 100755
--- a/parse_powerisa_pdf/parse_powerisa_pdf.py
+++ b/parse_powerisa_pdf/parse_powerisa_pdf.py
@@ -425,19 +425,19 @@ class TextLineFonts:
 
 TextLineFonts._define_fonts()
 
-class FontVariantCode(enum.Enum):
+class FontVariantCode(tuple, enum.Enum):
     CODE = ("code",)
     NOT_CODE = ()
 
-class FontVariantBold(enum.Enum):
+class FontVariantBold(tuple, enum.Enum):
     BOLD = ("b",)
     NOT_BOLD = ()
 
-class FontVariantItalic(enum.Enum):
+class FontVariantItalic(tuple, enum.Enum):
     ITALIC = ("i",)
     NOT_ITALIC = ()
 
-class FontVariantSubSuper(enum.Enum):
+class FontVariantSubSuper(tuple, enum.Enum):
     NOT_SUB_SUPER = ()
     SUBSCRIPT = ("sub",)
     SUPERSCRIPT = ("sup",)
@@ -1934,4 +1934,4 @@ def main():
         "powerisa-instructions.xml",
         encoding="utf-8",
         xml_declaration=True,
-    )
\ No newline at end of file
+    )