diff --git a/llpython/byte_control.py b/llpython/byte_control.py
index e21252a..efd54aa 100644
--- a/llpython/byte_control.py
+++ b/llpython/byte_control.py
@@ -1,11 +1,14 @@
 #! /usr/bin/env python
 # ______________________________________________________________________
+# Module imports
 
 from __future__ import absolute_import
-import opcode
-from . import opcode_util
-import pprint
 
+import opcode
+import pprint
+import types
+
+from . import opcode_util
 from .bytecode_visitor import BasicBlockVisitor, BenignBytecodeVisitorMixin
 from .control_flow import ControlFlowGraph
 
@@ -251,24 +254,39 @@ class ControlFlowBuilder (BenignBytecodeVisitorMixin, BasicBlockVisitor):
         return super(ControlFlowBuilder, self).op_SETUP_WITH(i, op, arg, *args,
                                                              **kws)
 
+    # ____________________________________________________________
+    # Class convenience methods
+
+    @classmethod
+    def build_cfg_from_co(cls, co_obj):
+        return cls().visit(opcode_util.build_basic_blocks(co_obj),
+                           co_obj.co_argcount)
+
+    @classmethod
+    def build_cfg(cls, func):
+        co_obj = opcode_util.get_code_object(func)
+        return cls.build_cfg_from_co(co_obj)
+
 # ______________________________________________________________________
 
 def build_cfg (func):
     '''Given a Python function, create a bytecode flow, visit the flow
     object, and return a control flow graph.'''
-    co_obj = opcode_util.get_code_object(func)
-    return ControlFlowBuilder().visit(opcode_util.build_basic_blocks(co_obj),
-                                      co_obj.co_argcount)
+    return ControlFlowBuilder.build_cfg(func)
 
 # ______________________________________________________________________
 # Main (self-test) routine
 
 def main (*args, **kws):
-    from tests import llfuncs
-    if not args:
-        args = ('doslice',)
-    for arg in args:
-        build_cfg(getattr(llfuncs, arg)).pprint()
+    def _visit(obj):
+        print("_" * 70)
+        print(obj)
+        if type(obj) == types.FunctionType:
+            cfg = build_cfg(obj)
+        else:
+            cfg = ControlFlowBuilder.build_cfg_from_co(obj)
+        cfg.pprint()
+    return opcode_util.visit_code_args(_visit, *args, **kws)
 
 # ______________________________________________________________________
 
diff --git a/llpython/byte_flow.py b/llpython/byte_flow.py
index b37d39d..452a7f7 100644
--- a/llpython/byte_flow.py
+++ b/llpython/byte_flow.py
@@ -4,6 +4,8 @@
 from __future__ import absolute_import
 import dis
 import opcode
+import pprint
+import types
 
 from .bytecode_visitor import BasicBlockVisitor
 from . import opcode_util
@@ -293,7 +295,16 @@ class BytecodeFlowBuilder (BasicBlockVisitor):
     op_UNARY_NOT = _op
     op_UNARY_POSITIVE = _op
     #op_UNPACK_EX = _not_implemented
-    #op_UNPACK_SEQUENCE = _not_implemented
+
+    def op_UNPACK_SEQUENCE (self, i, op, arg):
+        seq = self.stack.pop()
+        opname = self.opnames[op]
+        while arg > 0:
+            arg -= 1
+            ret_val = i, op, opname, arg, [seq]
+            self.stack.append(ret_val)
+        return ret_val
+
     #op_WITH_CLEANUP = _not_implemented
     op_YIELD_VALUE = _op
 
@@ -308,9 +319,7 @@ class BytecodeFlowBuilder (BasicBlockVisitor):
     def build_flow_from_co(cls, code_obj):
         '''Given a Python code object, return a flow representation of
         that code object.'''
-        bbs = opcode_util.build_basic_blocks(code_obj)
-        cfg = byte_control.ControlFlowBuilder().visit(bbs,
-                                                      code_obj.co_argcount)
+        cfg = byte_control.ControlFlowBuilder.build_cfg_from_co(code_obj)
         return cls().visit_cfg(cfg)
 
     @classmethod
@@ -333,23 +342,15 @@ def build_flow(func):
 
 def demo_flow_builder(builder_cls, *args):
     import pprint
-    try:
-        from .tests import llfuncs
-    except ImportError:
-        llfuncs = object()
-    if not args:
-        args = ('pymod',)
-    for arg in args:
-        if arg.endswith('.py'):
-            with open(arg) as in_file:
-                in_source = in_file.read()
-                in_codeobj = compile(in_source, arg, 'exec')
-                for codeobj in opcode_util.itercodeobjs(in_codeobj):
-                    print("_" * 70)
-                    print(codeobj)
-                    pprint.pprint(builder_cls.build_flow_from_co(codeobj))
+    def _visit(obj):
+        print("_" * 70)
+        print(obj)
+        if type(obj) == types.FunctionType:
+            flow = builder_cls.build_flow(obj)
         else:
-            pprint.pprint(builder_cls.build_flow(getattr(llfuncs, arg)))
+            flow = builder_cls.build_flow_from_co(obj)
+        pprint.pprint(flow)
+    return opcode_util.visit_code_args(_visit, *args)
 
 # ______________________________________________________________________
 # Main (self-test) routine
diff --git a/llpython/opcode_util.py b/llpython/opcode_util.py
index 657c851..e79257e 100644
--- a/llpython/opcode_util.py
+++ b/llpython/opcode_util.py
@@ -214,6 +214,34 @@ def itercodeobjs(codeobj):
 
 # ______________________________________________________________________
 
+def visit_code_args(visitor, *args, **kws):
+    """Utility function for testing or demonstrating various code
+    analysis passes in llpython.
+
+    Takes a visitor function and a sequence of command line arguments.
+    The visitor function should be able to handle either function
+    objects or code objects."""
+    try:
+        from .tests import llfuncs
+    except ImportError:
+        llfuncs = object()
+    if not args:
+        if 'default_args' in kws:
+            args = kws['default_args']
+        else:
+            args = ('pymod',)
+    for arg in args:
+        if arg.endswith('.py'):
+            with open(arg) as in_file:
+                in_source = in_file.read()
+                in_codeobj = compile(in_source, arg, 'exec')
+                for codeobj in itercodeobjs(in_codeobj):
+                    visitor(codeobj)
+        else:
+            visitor(getattr(llfuncs, arg))
+
+# ______________________________________________________________________
+
 def extendlabels(code, labels = None):
     """Extend the set of jump target labels to account for the
     passthrough targets of conditional branches.