Support adding lists to a component property, which value already was a list

and remove the Component.set method, which was only be used by add method.

CHANGES.rst

@@ -5,6 +5,10 @@ Changelog
 4.0.dev (unreleased)
 --------------------
 
+- Support adding lists to a component property, which value already was a list
+  and remove the Component.set method, which was only be used by add method.
+  [thet]
+
 - Remove ability to add property parameters via a value's params attribute when
   adding via cal.add (that was only possible for custom value objects and makes
   up a strange API), but support a parameter attribute on cal.add's method

src/icalendar/cal.py

@@ -112,16 +112,6 @@ class Component(CaselessDict):
             obj.params = parameters
         return obj
 
-    def set(self, name, value, parameters=None, encode=1):
-        if encode and isinstance(value, list) \
-                and name.lower() not in ['rdate', 'exdate']:
-            # Individually convert each value to an ical type except rdate and
-            # exdate, where lists of dates might be passed to vDDDLists.
-            self[name] = [self._encode(name, v, parameters, encode)
-                          for v in value]
-        else:
-            self[name] = self._encode(name, value, parameters, encode)
-
     def add(self, name, value, parameters=None, encode=1):
         """Add a property.
 
@@ -152,16 +142,29 @@ class Component(CaselessDict):
                 # assume UTC for naive datetime instances
                 value = pytz.utc.localize(value)
 
-        # If property already exists, append it. Otherwise create and set it.
-        if name in self:
-            oldval = self[name]
-            value = self._encode(name, value, parameters, encode)
-            if isinstance(oldval, list):
-                oldval.append(value)
-            else:
-                self.set(name, [oldval, value], None, encode=0)
+        # encode value
+        if encode and isinstance(value, list) \
+                and name.lower() not in ['rdate', 'exdate']:
+            # Individually convert each value to an ical type except rdate and
+            # exdate, where lists of dates might be passed to vDDDLists.
+            value = [self._encode(name, v, parameters, encode) for v in value]
         else:
-            self.set(name, value, parameters, encode)
+            value = self._encode(name, value, parameters, encode)
+
+        # set value
+        if name in self:
+            # If property already exists, append it.
+            #if name == 'attendee': import pdb; pdb.set_trace()
+            oldval = self[name]
+            if isinstance(oldval, list):
+                if isinstance(value, list):
+                    value = oldval + value
+                else:
+                    oldval.append(value)
+                    value = oldval
+            else:
+                value = [oldval, value]
+        self[name] = value
 
     def _decode(self, name, value):
         """Internal for decoding property values.

src/icalendar/tests/test_unit_cal.py

@@ -32,18 +32,39 @@ class TestCalComponent(unittest.TestCase):
                       'PRODID': '-//max m//icalendar.mxm.dk/'})
         )
 
+        ### ADD MULTIPLE VALUES TO A PROPERTY
+
         # if you use the add method you don't have to considder if a value is
         # a list or not.
         c = Component()
         c.name = 'VEVENT'
+
+        # add multiple values at once
+        c.add('attendee',
+              ['test@test.com', 'test2@test.com'])
+
+        # or add one per line
         c.add('attendee', 'maxm@mxm.dk')
         c.add('attendee', 'test@example.dk')
+
+        # add again multiple values at once to very concatenaton of lists
+        c.add('attendee',
+              ['test3@test.com', 'test4@test.com'])
+
         self.assertEqual(
             c,
-            Event({'ATTENDEE': [prop.vCalAddress('maxm@mxm.dk'),
-                                prop.vCalAddress('test@example.dk')]})
+            Event({'ATTENDEE': [
+                prop.vCalAddress('test@test.com'),
+                prop.vCalAddress('test2@test.com'),
+                prop.vCalAddress('maxm@mxm.dk'),
+                prop.vCalAddress('test@example.dk'),
+                prop.vCalAddress('test3@test.com'),
+                prop.vCalAddress('test4@test.com')
+            ]})
         )
 
+        ###
+
         # You can get the values back directly ...
         c.add('prodid', '-//my product//')
         self.assertEqual(c['prodid'], prop.vText(u'-//my product//'))
@@ -284,7 +305,7 @@ class TestCal(unittest.TestCase):
         event = icalendar.cal.Event()
         event['summary'] = 'Python meeting about calendaring'
         event['uid'] = '42'
-        event.set('dtstart', datetime(2005, 4, 4, 8, 0, 0))
+        event.add('dtstart', datetime(2005, 4, 4, 8, 0, 0))
         cal.add_component(event)
         self.assertEqual(
             cal.subcomponents[0].to_ical(),