tweaking docstrings

armi/materials/material.py

@@ -758,11 +758,8 @@ class Fluid(Material):
     """A material that fills its container. Could also be a gas."""
 
     def __init_subclass__(cls):
-        # Undo the parent-aware density wrapping
-        # Justification: fluids do not expand in the same way solids expand so
-        # fluid.density(T) is an appropriate representation of the density of
-        # the fluid. This does not hold for solids because of the thermal expansion
-        # mechanics imposed by the rest of the framework
+        # Undo the parent-aware density wrapping. Fluids do not expand in the same way solids, so
+        # Fluid.density(T) is correct. This does not hold for solids because they thermalaly expand.
         if hasattr(cls.density, "__wrapped__"):
             cls.density = cls.density.__wrapped__
 

armi/materials/tests/test_fluids.py

@@ -35,13 +35,13 @@ class MySolid(Material):
     def test_fluidDensityWrapperNoWarning(self):
         """Test that Component.material.density does not raise a warning for fluids.
 
-        The ARMI Framework contains a mechanism to warn users if they as for the density
-        of a material when that material is attached to a component, e.g., ``comp.material.density()``.
-        The problem here is the component is the source of truth for volume and composition. It stores
-        dimensions, which can be thermally expanded according to the material, and number densities, which
-        may be updated through operation. Much of the framework operates on ``component.density`` and
-        other ``Component`` methods for mass accounting. However, ``comp.material.density`` does
-        not know about the new composition or volumes and can diverge from ``component.density``.
+        The ARMI Framework contains a mechanism to warn users if they ask for the density of a
+        material attached to a component, e.g., ``comp.material.density()``. The problem is the
+        component is the source of truth for volume and composition. It stores dimensions, which can
+        be thermally expanded according to the material and number densities, which may be updated
+        during operation. Much of the framework operates on ``Component.density`` and other
+        ``Component`` methods for mass accounting. However, ``comp.material.density`` does not know
+        about the new composition or volumes and can diverge from ``component.density``.
 
         Additionally, the framework does not do any thermal expansion on fluids. So the above calls to
         ``component.material.density`` are warranted if the material is a fluid.