--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/env/lib/python3.7/site-packages/rdflib/collection.py	Sat May 02 07:14:21 2020 -0400
@@ -0,0 +1,285 @@
+from rdflib.namespace import RDF
+from rdflib.term import BNode
+from rdflib.term import Literal
+from rdflib.py3compat import format_doctest_out
+
+__all__ = ['Collection']
+
+
+class Collection(object):
+    __doc__ = format_doctest_out("""
+    See "Emulating container types":
+    https://docs.python.org/reference/datamodel.html#emulating-container-types
+
+    >>> from rdflib.graph import Graph
+    >>> from pprint import pprint
+    >>> listName = BNode()
+    >>> g = Graph('IOMemory')
+    >>> listItem1 = BNode()
+    >>> listItem2 = BNode()
+    >>> g.add((listName, RDF.first, Literal(1)))
+    >>> g.add((listName, RDF.rest, listItem1))
+    >>> g.add((listItem1, RDF.first, Literal(2)))
+    >>> g.add((listItem1, RDF.rest, listItem2))
+    >>> g.add((listItem2, RDF.rest, RDF.nil))
+    >>> g.add((listItem2, RDF.first, Literal(3)))
+    >>> c = Collection(g,listName)
+    >>> pprint([term.n3() for term in c])
+    [%(u)s'"1"^^<http://www.w3.org/2001/XMLSchema#integer>',
+     %(u)s'"2"^^<http://www.w3.org/2001/XMLSchema#integer>',
+     %(u)s'"3"^^<http://www.w3.org/2001/XMLSchema#integer>']
+
+    >>> Literal(1) in c
+    True
+    >>> len(c)
+    3
+    >>> c._get_container(1) == listItem1
+    True
+    >>> c.index(Literal(2)) == 1
+    True
+    """)
+
+    def __init__(self, graph, uri, seq=[]):
+        self.graph = graph
+        self.uri = uri or BNode()
+        self += seq
+
+    def n3(self):
+        """
+        >>> from rdflib.graph import Graph
+        >>> listName = BNode()
+        >>> g = Graph('IOMemory')
+        >>> listItem1 = BNode()
+        >>> listItem2 = BNode()
+        >>> g.add((listName, RDF.first, Literal(1)))
+        >>> g.add((listName, RDF.rest, listItem1))
+        >>> g.add((listItem1, RDF.first, Literal(2)))
+        >>> g.add((listItem1, RDF.rest, listItem2))
+        >>> g.add((listItem2, RDF.rest, RDF.nil))
+        >>> g.add((listItem2, RDF.first, Literal(3)))
+        >>> c = Collection(g, listName)
+        >>> print(c.n3()) #doctest: +NORMALIZE_WHITESPACE
+        ( "1"^^<http://www.w3.org/2001/XMLSchema#integer>
+          "2"^^<http://www.w3.org/2001/XMLSchema#integer>
+          "3"^^<http://www.w3.org/2001/XMLSchema#integer> )
+        """
+        return "( %s )" % (' '.join([i.n3() for i in self]))
+
+    def _get_container(self, index):
+        """Gets the first, rest holding node at index."""
+        assert isinstance(index, int)
+        graph = self.graph
+        container = self.uri
+        i = 0
+        while i < index:
+            i += 1
+            container = graph.value(container, RDF.rest)
+            if container is None:
+                break
+        return container
+
+    def __len__(self):
+        """length of items in collection."""
+        return len(list(self.graph.items(self.uri)))
+
+    def index(self, item):
+        """
+        Returns the 0-based numerical index of the item in the list
+        """
+        listName = self.uri
+        index = 0
+        while True:
+            if (listName, RDF.first, item) in self.graph:
+                return index
+            else:
+                newLink = list(self.graph.objects(listName, RDF.rest))
+                index += 1
+                if newLink == [RDF.nil]:
+                    raise ValueError("%s is not in %s" % (item, self.uri))
+                elif not newLink:
+                    raise Exception("Malformed RDF Collection: %s" % self.uri)
+                else:
+                    assert len(newLink) == 1, \
+                        "Malformed RDF Collection: %s" % self.uri
+                    listName = newLink[0]
+
+    def __getitem__(self, key):
+        """TODO"""
+        c = self._get_container(key)
+        if c:
+            v = self.graph.value(c, RDF.first)
+            if v:
+                return v
+            else:
+                raise KeyError(key)
+        else:
+            raise IndexError(key)
+
+    def __setitem__(self, key, value):
+        """TODO"""
+        c = self._get_container(key)
+        if c:
+            self.graph.set((c, RDF.first, value))
+        else:
+            raise IndexError(key)
+
+    def __delitem__(self, key):
+        """
+        >>> from rdflib.namespace import RDF, RDFS
+        >>> from rdflib import Graph
+        >>> from pprint import pformat
+        >>> g = Graph()
+        >>> a = BNode('foo')
+        >>> b = BNode('bar')
+        >>> c = BNode('baz')
+        >>> g.add((a, RDF.first, RDF.type))
+        >>> g.add((a, RDF.rest, b))
+        >>> g.add((b, RDF.first, RDFS.label))
+        >>> g.add((b, RDF.rest, c))
+        >>> g.add((c, RDF.first, RDFS.comment))
+        >>> g.add((c, RDF.rest, RDF.nil))
+        >>> len(g)
+        6
+        >>> def listAncestry(node, graph):
+        ...   for i in graph.subjects(RDF.rest, node):
+        ...     yield i
+        >>> [str(node.n3())
+        ...   for node in g.transitiveClosure(listAncestry, RDF.nil)]
+        ['_:baz', '_:bar', '_:foo']
+        >>> lst = Collection(g, a)
+        >>> len(lst)
+        3
+        >>> b == lst._get_container(1)
+        True
+        >>> c == lst._get_container(2)
+        True
+        >>> del lst[1]
+        >>> len(lst)
+        2
+        >>> len(g)
+        4
+
+        """
+        self[key]  # to raise any potential key exceptions
+        graph = self.graph
+        current = self._get_container(key)
+        assert current
+        if len(self) == 1 and key > 0:
+            pass
+        elif key == len(self) - 1:
+            # the tail
+            priorLink = self._get_container(key - 1)
+            self.graph.set((priorLink, RDF.rest, RDF.nil))
+            graph.remove((current, None, None))
+        else:
+            next = self._get_container(key + 1)
+            prior = self._get_container(key - 1)
+            assert next and prior
+            graph.remove((current, None, None))
+            graph.set((prior, RDF.rest, next))
+
+    def __iter__(self):
+        """Iterator over items in Collections"""
+        return self.graph.items(self.uri)
+
+    def _end(self):
+        # find end of list
+        container = self.uri
+        while True:
+            rest = self.graph.value(container, RDF.rest)
+            if rest == None or rest == RDF.nil:
+                return container
+            else:
+                container = rest
+
+    def append(self, item):
+        """
+        >>> from rdflib.graph import Graph
+        >>> listName = BNode()
+        >>> g = Graph()
+        >>> c = Collection(g,listName,[Literal(1),Literal(2)])
+        >>> links = [
+        ...     list(g.subjects(object=i, predicate=RDF.first))[0] for i in c]
+        >>> len([i for i in links if (i, RDF.rest, RDF.nil) in g])
+        1
+
+        """
+
+        end = self._end()
+        if (end, RDF.first, None) in self.graph:
+            # append new node to the end of the linked list
+            node = BNode()
+            self.graph.set((end, RDF.rest, node))
+            end = node
+
+        self.graph.add((end, RDF.first, item))
+        self.graph.add((end, RDF.rest, RDF.nil))
+
+    def __iadd__(self, other):
+
+        end = self._end()
+        self.graph.remove((end, RDF.rest, None))
+
+        for item in other:
+            if (end, RDF.first, None) in self.graph:
+                nxt = BNode()
+                self.graph.add((end, RDF.rest, nxt))
+                end = nxt
+
+            self.graph.add((end, RDF.first, item))
+
+
+        self.graph.add((end, RDF.rest, RDF.nil))
+
+    def clear(self):
+        container = self.uri
+        graph = self.graph
+        while container:
+            rest = graph.value(container, RDF.rest)
+            graph.remove((container, RDF.first, None))
+            graph.remove((container, RDF.rest, None))
+            container = rest
+
+
+def test():
+    import doctest
+    doctest.testmod()
+
+if __name__ == "__main__":
+    test()
+
+    from rdflib import Graph
+    g = Graph()
+
+    c = Collection(g, BNode())
+
+    assert len(c) == 0
+
+    c = Collection(
+        g, BNode(), [Literal("1"), Literal("2"), Literal("3"), Literal("4")])
+
+    assert len(c) == 4
+
+    assert c[1] == Literal("2"), c[1]
+
+    del c[1]
+
+    assert list(c) == [Literal("1"), Literal("3"), Literal("4")], list(c)
+
+    try:
+        del c[500]
+    except IndexError as i:
+        pass
+
+    c.append(Literal("5"))
+
+    print((list(c)))
+
+    for i in c:
+        print(i)
+
+    del c[3]
+
+    c.clear()
+
+    assert len(c) == 0