Update README.md

README.md

@@ -5,12 +5,24 @@ Usage example:
 ```python
 import pymolfile
 
-molfile = pymolfile.OpenMolfile('test/ala3.pdb')
+moltopo = pymolfile.OpenMolfile('test/DPDP.pdb')
 
-print(molfile.topology.structure)
-print(molfile.topology.bonds)
-print(molfile.topology.angles)
+print(moltopo.topology.structure)
+print(moltopo.topology.bonds)
+print(moltopo.topology.angles)
+
+moltraj = pym.OpenMolfile('test/DPDP.nc', topology=moltopo)
+
+    if moltraj.trajectory is not None:
+        step=0
+        while True:
+            positions = moltraj.trajectory.iread()
+            if positions is not None:
+                print("STEP:",step)
+                print(positions)
+                step += 1
+            else:
+                break
 
-molfile_traj = molfile.trajectory.iread()
 ```