Preheat the oven to 350°F (175°C). Grease and flour a 9×5 inch loaf pan.
In a medium bowl, whisk together the all-purpose flour, baking soda, baking powder, salt, ground cinnamon, ground nutmeg, ground cloves, and ground ginger until well combined.
In a large bowl, beat the granulated sugar, light brown sugar, and vegetable oil until combined.
Add the eggs one at a time to the sugar and oil mixture, beating well after each addition.
Mix in the pumpkin puree and vanilla extract until smooth.
Gradually add the dry ingredients to the wet ingredients, stirring just until combined. Do not overmix.
Fold in the raisins and chopped walnuts if using.
Pour the batter into the prepared loaf pan and smooth the top with a spatula.
Bake in the preheated oven for 55 to 60 minutes, or until a toothpick inserted into the center comes out clean.
Remove the bread from the oven and let it cool in the pan for 10 minutes.
Transfer the bread to a wire rack to cool completely before slicing.