Start argument parsing.

translate2modelcif.py

 """Translate models from Tara/ Xabi from PDB + extra data into ModelCIF."""
 
+import argparse
+
+
+def _parse_args():
+    """Parse command line arguments."""
+    parser = argparse.ArgumentParser(
+        formatter_class=argparse.RawDescriptionHelpFormatter,
+        description=__doc__,
+    )
+
+    return parser.parse_args()
+
 
 def _main():
     """Run as script."""
-    print("Hello World")
+    _parse_args()
 
 
 if __name__ == "__main__":