Preheat your oven to 350°F (175°C).
In a mixing bowl, combine the canned pumpkin puree, vegetable oil, granulated sugar, and brown sugar. Mix until well blended.
Add the eggs one at a time, mixing well after each addition.
In a separate bowl, whisk together the flour, baking soda, baking powder, cinnamon, nutmeg, and salt.
Gradually fold the dry ingredients into the pumpkin mixture until just combined.
If desired, stir in nuts or chocolate chips at this point.
Pour the batter into a greased loaf pan.
Bake for 60-70 minutes, or until a toothpick inserted into the center comes out clean.
Allow the bread to cool in the pan for about 10 minutes, then transfer to a wire rack to cool completely.