[section] Add prop cardinality on init

Author: mpsonntag

odml/section.py

@@ -40,8 +40,12 @@ class BaseSection(base.Sectionable):
     :param link: Specifies a soft link, i.e. a path within the document.
     :param include: Specifies an arbitrary URL. Can only be used if *link* is not set.
     :param oid: object id, UUID string as specified in RFC 4122. If no id is provided,
-               an id will be generated and assigned. An id has to be unique
-               within an odML Document.
+                an id will be generated and assigned. An id has to be unique
+                within an odML Document.
+    :param prop_cardinality: Property cardinality defines how many Properties are allowed for this
+                             Section. By default unlimited Properties can be set.
+                             A required number of Properties can be set by assigning a tuple of the
+                             format "(min, max)".
     """
 
     type = None
@@ -54,7 +58,8 @@ class BaseSection(base.Sectionable):
 
     def __init__(self, name=None, type="n.s.", parent=None,
                  definition=None, reference=None,
-                 repository=None, link=None, include=None, oid=None):
+                 repository=None, link=None, include=None, oid=None,
+                 prop_cardinality=None):
 
         # Sets _sections Smartlist and _repository to None, so run first.
         super(BaseSection, self).__init__()
@@ -80,6 +85,7 @@ def __init__(self, name=None, type="n.s.", parent=None,
         self._repository = repository
         self._link = link
         self._include = include
+        self._prop_cardinality = prop_cardinality
 
         # this may fire a change event, so have the section setup then
         self.type = type