To create a new Tulip graph from Python, the `tlp.newGraph()` function has to be used.
It returns an empty graph which is an instance of the `tlp.Graph` class.

```
graph = tlp.newGraph()
```

TLP is the Tulip format to save a graph and its associated data to a file. The extension of the file can be .tlp or .tlp.gz (compressed version).

To load a graph saved in TLP into a Python oject, the `tlp.loadGraph()` function has to be used. It loads
the graph described in the file and its associated data and returns an instance of the `tlp.Graph`.
For instance, the sample code below imports the graph saved to the file /home/foo/savedgraph.tlp:

```
graph = tlp.loadGraph("/home/foo/savedgraph.tlp")
```

To save an instance of a `tlp.Graph` class to a TLP file, the `tlp.saveGraph()` function has to be used. It saves
the graph and its associated data into a file.
For instance, the sample code below exports a graph to the file /home/foo/mygraph.tlp:

```
tlp.saveGraph(graph, "/home/foo/mygraph.tlp")
```

The graph structure can be freely modified through dedicated methods of the `tlp.Graph` class (see *Modification of the graph structure*) . Below is a list of some of these methods :

- Adding elements to the graph :
tlp.Graph.addNode(),tlp.Graph.addEdge()- Removing elements from the graph :
tlp.Graph.delNode(),tlp.Graph.delEdge(),tlp.Graph.clear()

The `tlp.Graph` class provides several iterators on the graph structure (see *Iterators on the graph structure*).
The sample code below illustrates the syntax to perform an iteration over all the nodes of a graph.:

```
for n in graph.getNodes():
degree = graph.deg(n)
print "the degree of ", n, "is ", degree
```