fix error message in mesolve (#273)

Author: ytdHuang

src/time_evolution/mesolve.jl

@@ -46,9 +46,16 @@ function _mesolve_make_L_QobjEvo(H::Tuple, c_ops)
     c_ops isa Nothing && return QobjEvo(H)
     return QobjEvo((H..., mapreduce(op -> lindblad_dissipator(op), +, c_ops)); type = SuperOperator, f = liouvillian)
 end
-# TODO: Add support for Operator type QobEvo
-function _mesolve_make_L_QobjEvo(H::QuantumObjectEvolution, c_ops)
-    issuper(H) || throw(ArgumentError("The time-dependent Hamiltonian must be a SuperOperator."))
+_mesolve_make_L_QobjEvo(H::QuantumObjectEvolution{DT,OperatorQuantumObject}, c_ops) where {DT<:AbstractSciMLOperator} =
+    throw(
+        ArgumentError(
+            "This function does not support the data type of time-dependent Operator `H` currently. Try to provide `H` as a time-dependent SuperOperator or Tuple instead.",
+        ),
+    )
+function _mesolve_make_L_QobjEvo(
+    H::QuantumObjectEvolution{DT,SuperOperatorQuantumObject},
+    c_ops,
+) where {DT<:AbstractSciMLOperator}
     c_ops isa Nothing && return H
     return H + QobjEvo((mapreduce(op -> lindblad_dissipator(op), +, c_ops)))
 end