diff --git a/apps/cic-eth/cic_eth/api/api_task.py b/apps/cic-eth/cic_eth/api/api_task.py
index 6c596a7b..a2535807 100644
--- a/apps/cic-eth/cic_eth/api/api_task.py
+++ b/apps/cic-eth/cic_eth/api/api_task.py
@@ -22,7 +22,27 @@ logg = logging.getLogger()
 
 
 class Api(ApiBase):
-    
+
+    @staticmethod
+    def to_v_list(v, n):
+        if isinstance(v, str):
+            vv = v
+            v = []
+            for i in range(n):
+                v.append([vv])
+        elif not isinstance(v, list):
+            raise ValueError('argument must be single string, or list or strings or lists')
+        else:
+            if len(v) != n:
+                raise ValueError('v argument count must match integer n')
+            for i in range(n):
+                if isinstance(v[i], str):
+                    v[i] = [v[i]]
+                elif not isinstance(v, list):
+                    raise ValueError('proof argument must be single string, or list or strings or lists')
+
+        return v
+   
 
     def default_token(self):
         s_token = celery.signature(
@@ -37,12 +57,21 @@ class Api(ApiBase):
 
 
     def token(self, token_symbol, proof=None):
+        if not isinstance(token_symbol, str):
+            raise ValueError('token symbol must be string')
+
         return self.tokens([token_symbol], proof=proof)
 
 
     def tokens(self, token_symbols, proof=None):
-        if isinstance(proof, str):
-            proof = [proof]
+        if not isinstance(token_symbols, list):
+            raise ValueError('token symbols argument must be list')
+
+        if proof == None:
+            logg.debug('looking up tokens without external proof check: {}'.format(','.join(token_symbols)))
+            proof = ''
+        proof = Api.to_v_list(proof, len(token_symbols)) 
+
         chain_spec_dict = self.chain_spec.asdict()
 
         s_token_resolve = celery.signature(
diff --git a/apps/cic-eth/tests/task/api/test_app_noncritical.py b/apps/cic-eth/tests/task/api/test_app_noncritical.py
index 429ef08e..241fc1f6 100644
--- a/apps/cic-eth/tests/task/api/test_app_noncritical.py
+++ b/apps/cic-eth/tests/task/api/test_app_noncritical.py
@@ -40,6 +40,61 @@ def test_default_token(
     assert r['address'] == foo_token
 
 
+def test_to_v_list():
+    assert Api.to_v_list('foo', 1) == [['foo']]
+    assert Api.to_v_list(['foo'], 1) == [['foo']]
+    assert Api.to_v_list(['foo', 'bar'], 2) == [['foo'], ['bar']]
+    assert Api.to_v_list('foo', 3) == [['foo'], ['foo'], ['foo']]
+    assert Api.to_v_list([['foo'], ['bar']], 2) == [['foo'], ['bar']]
+    with pytest.raises(ValueError):
+        Api.to_v_list([['foo'], ['bar']], 3)
+    with pytest.raises(ValueError):
+        Api.to_v_list(['foo', 'bar'], 3)
+    with pytest.raises(ValueError):
+        Api.to_v_list([['foo'], ['bar'], ['baz']], 2)
+
+    assert Api.to_v_list([
+            ['foo'],
+            'bar',
+            ['inky', 'pinky', 'blinky', 'clyde'],
+        ], 3) == [
+            ['foo'],
+            ['bar'],
+            ['inky', 'pinky', 'blinky', 'clyde'],
+            ]
+
+
+def test_token_single(
+        default_chain_spec,
+        foo_token,
+        bar_token,
+        token_registry,
+        register_tokens,
+        register_lookups,
+        cic_registry,
+        init_database,
+        init_celery_tasks,
+        custodial_roles,
+        foo_token_declaration,
+        bar_token_declaration,
+        celery_session_worker,
+        ):
+
+    api = Api(str(default_chain_spec), queue=None, callback_param='foo')     
+
+    t = api.token('FOO', proof=None)
+    r = t.get()
+    logg.debug('rr {}'.format(r))
+    assert len(r) == 1
+    assert r[0]['address'] == strip_0x(foo_token)
+
+
+    t = api.token('FOO', proof=foo_token_declaration)
+    r = t.get()
+    assert len(r) == 1
+    assert r[0]['address'] == strip_0x(foo_token)
+
+
 def test_tokens(
         default_chain_spec,
         foo_token,
@@ -118,3 +173,4 @@ def test_tokens(
         f.close()
         assert v == b'\x00'
         break
+