diff --git a/python/tvm/_ffi/_ctypes/vmobj.py b/python/tvm/_ffi/_ctypes/vmobj.py
index 498167c7819e3..59930e55c3829 100644
--- a/python/tvm/_ffi/_ctypes/vmobj.py
+++ b/python/tvm/_ffi/_ctypes/vmobj.py
@@ -39,7 +39,6 @@ def _return_object(x):
     tag = ctypes.c_int()
     check_call(_LIB.TVMGetObjectTag(handle, ctypes.byref(tag)))
     cls = OBJECT_TYPE.get(tag.value, ObjectBase)
-    print('here')
     obj = cls(handle)
     return obj
 
diff --git a/python/tvm/relay/backend/vm.py b/python/tvm/relay/backend/vm.py
index 5e1a3c6b338d6..572d9bf399ae6 100644
--- a/python/tvm/relay/backend/vm.py
+++ b/python/tvm/relay/backend/vm.py
@@ -42,8 +42,8 @@ def _update_target(target):
             dev_type = tvm.expr.IntImm("int32", tvm.nd.context(dev).device_type)
             tgts[dev_type] = tvm.target.create(tgt)
     else:
-        raise TypeError("target is expected to be str or " +
-                        "tvm.target.Target, but received " +
+        raise TypeError("target is expected to be str, tvm.target.Target, " +
+                        "or dict of str to str/tvm.target.Target, but received " +
                         "{}".format(type(target)))
     return tgts
 
@@ -134,7 +134,7 @@ def compile(self, mod, target=None, target_host=None):
             The Relay module to build.
 
         target : str, :any:`tvm.target.Target`, or dict of str(i.e.
-        device/context name) to str/tvm.target.Target, optional
+            device/context name) to str/tvm.target.Target, optional
             For heterogeneous compilation, it is a dictionary indicating context
             to target mapping. For homogeneous compilation, it is a build target.
 
@@ -178,7 +178,8 @@ class VMExecutor(Executor):
         The target option to build the function.
     """
     def __init__(self, mod, ctx, target):
-        assert mod is not None
+        if mod is None:
+            raise RuntimeError("Must provide module to get VM executor.")
         self.mod = mod
         self.ctx = ctx
         self.target = target
diff --git a/python/tvm/relay/backend/vmobj.py b/python/tvm/relay/backend/vmobj.py
index c4d96b2890989..1bd12c8db3007 100644
--- a/python/tvm/relay/backend/vmobj.py
+++ b/python/tvm/relay/backend/vmobj.py
@@ -22,13 +22,15 @@
 from tvm import ndarray as _nd
 from . import _vmobj
 
+# TODO(@icemelon9): Add ClosureObject
+
 @register_object
 class TensorObject(Object):
     """Tensor object."""
     tag = ObjectTag.TENSOR
 
     def __init__(self, handle):
-        """Constructs a tensor object
+        """Constructs a Tensor object
 
         Parameters
         ----------
@@ -60,7 +62,7 @@ class DatatypeObject(Object):
     tag = ObjectTag.DATATYPE
 
     def __init__(self, handle):
-        """Constructs a tensor object
+        """Constructs a Datatype object
 
         Parameters
         ----------
@@ -69,8 +71,8 @@ def __init__(self, handle):
 
         Returns
         -------
-        obj : TensorObject
-            A tensor object.
+        obj : DatatypeObject
+            A Datatype object.
         """
         super(DatatypeObject, self).__init__(handle)
         self.tag = _vmobj.GetDatatypeTag(self)
diff --git a/src/relay/backend/vm/compiler.cc b/src/relay/backend/vm/compiler.cc
index b9ff8728113f0..05d388e3141e8 100644
--- a/src/relay/backend/vm/compiler.cc
+++ b/src/relay/backend/vm/compiler.cc
@@ -230,7 +230,6 @@ class VMCompiler : ExprFunctor<void(const Expr& expr)> {
   void VisitExpr_(const LetNode* let_node) {
     DLOG(INFO) << let_node->value;
     this->VisitExpr(let_node->value);
-    DLOG(INFO) << this->last_register_;
     var_register_map_.insert({let_node->var, this->last_register_});
     this->VisitExpr(let_node->body);
   }
@@ -443,23 +442,21 @@ class VMCompiler : ExprFunctor<void(const Expr& expr)> {
  protected:
   /*! \brief Store the expression a variable points to. */
   std::unordered_map<Var, Expr, NodeHash, NodeEqual> expr_map_;
-
+  /*! \brief Instructions in the VMFunction. */
   std::vector<Instruction> instructions_;
-
+  /*! \brief Parameter names of the function. */
   std::vector<std::string> params_;
-
-  // var -> register num
+  /*! \brief Map from var to register number. */
   std::unordered_map<Var, RegName, NodeHash, NodeEqual> var_register_map_;
-
+  /*! \brief Last used register number. */
   size_t last_register_;
-
-  // Total number of virtual registers allocated
+  /*! \brief Total number of virtual registers allocated. */
   size_t registers_num_;
+  /*! \brief Compiler engine to lower primitive functions. */
   CompileEngine engine_;
-
   /*! \brief Global shared meta data */
   VMCompilerContext* context_;
-
+  /*! \brief Target devices. */
   TargetsMap targets_;
 };
 
@@ -599,9 +596,13 @@ class VMBuildModule : public runtime::ModuleNode {
   }
 
  protected:
+  /*! \brief Target devices. */
   TargetsMap targets_;
+  /*! \brief Target host device. */
   tvm::Target target_host_;
+  /*! \brief Global shared meta data */
   VMCompilerContext context_;
+  /*! \brief Compiled virtual machine. */
   std::shared_ptr<VirtualMachine> vm_;
 };
 
diff --git a/tests/python/relay/test_vm.py b/tests/python/relay/test_vm.py
index 24ef664e651a9..255dc23d38d4a 100644
--- a/tests/python/relay/test_vm.py
+++ b/tests/python/relay/test_vm.py
@@ -22,7 +22,6 @@
 from tvm import relay
 from tvm.relay.scope_builder import ScopeBuilder
 from tvm.relay.prelude import Prelude
-#from tvm.relay.vm import BuildModule
 
 def veval(f, *args, ctx=tvm.cpu(), target="llvm"):
     if isinstance(f, relay.Expr):