diff --git a/src/dp5_impl/mod.jl b/src/dp5_impl/mod.jl
index 9ab81a4..cb193b9 100644
--- a/src/dp5_impl/mod.jl
+++ b/src/dp5_impl/mod.jl
@@ -1,8 +1,7 @@
 module DP5Impl
 
+using ..DormandPrince: DormandPrince, DP5Solver, Vars, Consts, Options, Report
 # external imports
-using DormandPrince: DP5Solver, Consts, Options, Vars, Report, Idid, Checks
-
 
 include("helpers.jl")
 include("checks.jl")
diff --git a/src/dp5_impl/solver.jl b/src/dp5_impl/solver.jl
index ee0e020..f84ba33 100644
--- a/src/dp5_impl/solver.jl
+++ b/src/dp5_impl/solver.jl
@@ -16,10 +16,10 @@ function dp5_integrate(
             check_beta(solver.options) ||
             check_safety_factor(solver.options)
     =#
-    check_max_allowed_steps(solver.options) || return Report(solver.vars.x, MAX_ALLOWED_STEPS_NEGATIVE, INPUT_NOT_CONSISTENT, 0, 0, 0, 0)
-    check_uround(solver.options) || return Report(solver.vars.x, UNSUPPORTED_UROUND, INPUT_NOT_CONSISTENT, 0, 0, 0, 0)
-    check_beta(solver.options) || return Report(solver.vars.x, CURIOUS_BETA, INPUT_NOT_CONSISTENT, 0, 0, 0, 0)
-    check_safety_factor(solver.options) || return Report(solver.vars.x, CURIOUS_SAFETY_FACTOR, INPUT_NOT_CONSISTENT, 0, 0, 0, 0)
+    check_max_allowed_steps(solver.options) || return Report(solver.vars.x, DormandPrince.MAX_ALLOWED_STEPS_NEGATIVE, DormandPrince.INPUT_NOT_CONSISTENT, 0, 0, 0, 0)
+    check_uround(solver.options) || return Report(solver.vars.x, DormandPrince.UNSUPPORTED_UROUND, DormandPrince.INPUT_NOT_CONSISTENT, 0, 0, 0, 0)
+    check_beta(solver.options) || return Report(solver.vars.x, DormandPrince.CURIOUS_BETA, DormandPrince.INPUT_NOT_CONSISTENT, 0, 0, 0, 0)
+    check_safety_factor(solver.options) || return Report(solver.vars.x, DormandPrince.CURIOUS_SAFETY_FACTOR, DormandPrince.INPUT_NOT_CONSISTENT, 0, 0, 0, 0)
 
     ###### nstiff -  parameters for stiffness detection
     # nstiff = solver_options.stiffness_test_activation_step
@@ -94,22 +94,22 @@ function dopcor(
     nfcn += 2
     reject = false
     
-    idid = LARGER_NMAX_NEEDED
+    idid = DormandPrince.LARGER_NMAX_NEEDED
 
     ###### Basic Integration Step
     for _ in 1:solver.options.maximum_allowed_steps
         # if nstep > solver.options.maximum_allowed_steps
         #     # GOTO 78
         #     # println(" MORE THAN NMAX = ", solver.options.maximum_allowed_steps, " STEPS ARE NEEDED")
-        #     return h, Report(solver.vars.x, INPUT_CHECKS_SUCCESSFUL, LARGER_NMAX_NEEDED , 0, 0, 0, 0)
+        #     return h, Report(solver.vars.x, DormandPrince.INPUT_CHECKS_SUCCESSFUL, DormandPrince.LARGER_NMAX_NEEDED , 0, 0, 0, 0)
         # end
         
         if (0.10 * abs(h)) <= abs(solver.vars.x)*solver.options.uround 
             # GOTO 77
             # println("STEP SIZE TOO SMALL, H = ", h)
-            # return h, Report(solver.vars.x, INPUT_CHECKS_SUCCESSFUL, STEP_SIZE_BECOMES_TOO_SMALL, 0, 0, 0, 0)
+            # return h, Report(solver.vars.x, DormandPrince.INPUT_CHECKS_SUCCESSFUL, DormandPrince.STEP_SIZE_BECOMES_TOO_SMALL, 0, 0, 0, 0)
 
-            idid = STEP_SIZE_BECOMES_TOO_SMALL
+            idid = DormandPrince.STEP_SIZE_BECOMES_TOO_SMALL
             break
         end
 
@@ -149,12 +149,12 @@ function dopcor(
             ###### Normal Exit
             if solver.vars.last 
                 h = hnew
-                idid = COMPUTATION_SUCCESSFUL
+                idid = DormandPrince.COMPUTATION_SUCCESSFUL
                 break
                 # return h, Report(
                 #     solver.vars.x, 
-                #     INPUT_CHECKS_SUCCESSFUL,
-                #     COMPUTATION_SUCCESSFUL, 
+                #     DormandPrince.INPUT_CHECKS_SUCCESSFUL,
+                #     DormandPrince.COMPUTATION_SUCCESSFUL, 
                 #     nfcn, 
                 #     nstep, 
                 #     naccpt, 
@@ -185,7 +185,7 @@ function dopcor(
 
     return h, Report(
         solver.vars.x, 
-        INPUT_CHECKS_SUCCESSFUL,
+        DormandPrince.INPUT_CHECKS_SUCCESSFUL,
         idid, 
         nfcn, 
         nstep, 
diff --git a/src/interface.jl b/src/interface.jl
index a07fdc8..e8e5285 100644
--- a/src/interface.jl
+++ b/src/interface.jl
@@ -29,11 +29,10 @@ end
 # 2. integrate(solver, times) -> iterator
 # 3. integrate(callback, solver, times) -> vector of states with callback applied
 
-integrate(solver::AbstractDPSolver, time::Real) = dp5_integrate(solver, time) 
-integrate(solver::AbstractDPSolver, times::AbstractVector{T}) where {T <: Real} = DP5Iterator(solver, times)
+integrate(solver::AbstractDPSolver{T}, time::T) where {T<:Real} = dp5_integrate(solver, time) 
+integrate(solver::AbstractDPSolver{T}, times::AbstractVector{T}) where {T <: Real} = DP5Iterator(solver, times)
 
-
-function integrate(callback, solver::AbstractDPSolver{StateVec, T}, times::AbstractVector{T}; sort_times::Bool = true) where {StateVec <: AbstractVector, T <: Real}
+function integrate(callback, solver::AbstractDPSolver{T}, times::AbstractVector{T}; sort_times::Bool = true) where {T <: Real}
     times = sort_times ? sort(collect(times)) : times
 
     result = []
diff --git a/test/errors.jl b/test/errors.jl
index 70a1e83..e101e35 100644
--- a/test/errors.jl
+++ b/test/errors.jl
@@ -1,10 +1,11 @@
 using Test
-using DormandPrince.DP5Impl:
+using DormandPrince:
     DP5Solver,
     Options,
     LARGER_NMAX_NEEDED,
-    STEP_SIZE_BECOMES_TOO_SMALL,
-    dopcor
+    STEP_SIZE_BECOMES_TOO_SMALL
+    
+using DormandPrince.DP5Impl: dopcor
 
 function fcn(x, y, f) 
     f[1] = y[1]^2 - y[1]^3