Merge pull request #241 from chriselrod/fixsymindexing

Fix symbol indexing by checking that observed !== nothing

Author: ChrisRackauckas

.JuliaFormatter.toml

@@ -0,0 +1 @@
+style = "sciml"

Project.toml

@@ -38,6 +38,7 @@ julia = "1.6"
 
 [extras]
 ForwardDiff = "f6369f11-7733-5829-9624-2563aa707210"
+LabelledArrays = "2ee39098-c373-598a-b85f-a56591580800"
 NLsolve = "2774e3e8-f4cf-5e23-947b-6d7e65073b56"
 OrdinaryDiffEq = "1dea7af3-3e70-54e6-95c3-0bf5283fa5ed"
 Pkg = "44cfe95a-1eb2-52ea-b672-e2afdf69b78f"
@@ -49,4 +50,4 @@ Unitful = "1986cc42-f94f-5a68-af5c-568840ba703d"
 Zygote = "e88e6eb3-aa80-5325-afca-941959d7151f"
 
 [targets]
-test = ["ForwardDiff", "NLsolve", "OrdinaryDiffEq", "Pkg", "Test", "Unitful", "Random", "StaticArrays", "StructArrays", "Zygote"]
+test = ["ForwardDiff", "LabelledArrays", "NLsolve", "OrdinaryDiffEq", "Pkg", "Test", "Unitful", "Random", "StaticArrays", "StructArrays", "Zygote"]