[Bug] Constructing the Hydrogel functional with a grade argument results in error

[joshichaitanya3]

The Hydrogel functional allows a number grade as an optional argument, but the construction fails with a HydrglArgs error.

To Reproduce
Run the following code in the test/functionals/hydrogel directory:

var m0 = Mesh("tetrahedron.mesh")
var lh = Hydrogel(m0, grade=2)

[softmattertheory]

Is this still a problem @joshichaitanya3 ?

[softmattertheory]

Reviewing this, it seems that this code doesn't generate an error immediately, but if I also do this:

print lh.total(m0)

I indeed get a weird error:

Error 'HydrglPrp': Hydrogel requires the first argument to be a mesh, 'grade' to be an integer grade, 'a', 'b', 'c' 'd', 'phiref' to be numbers and 'phi0' to be a number or a Field.

I'll continue to investigate this and fix.