alternate AnnotationData backend

docs/examples/example_chord_import.py

@@ -3,21 +3,20 @@
 import jams
 import sys
 
+
 def import_chord_jams(infile, outfile):
 
     # import_lab returns a new jams object,
     # and a handle to the newly created annotation
     jam, chords = jams.util.import_lab('chord', infile)
 
     # Infer the track duration from the end of the last annotation
-    duration = (chords.data['time'] + chords.data['duration']).max()
+    duration = max([obs.time + obs.duration for obs in chords])
 
-    # this timing will be in pandas timedelta.
-    # calling duration.total_seconds() converts to float
-    jam.file_metadata.duration = duration.total_seconds()
+    jam.file_metadata.duration = duration
 
     chords.time = 0
-    chords.duration = duration.total_seconds()
+    chords.duration = duration
 
     # save to disk
     jam.save(outfile)
@@ -27,4 +26,3 @@ def import_chord_jams(infile, outfile):
 
     infile, outfile = sys.argv[1:]
     import_chord_jams(infile, outfile)
-

jams/__init__.py

@@ -1,6 +1,9 @@
 #!/usr/bin/env python
 """Top-level module for JAMS"""
 
+import os
+from pkg_resources import resource_filename
+
 # Import the necessary modules
 from .exceptions import *
 from . import util
@@ -12,15 +15,13 @@
 from .core import *
 from .nsconvert import convert
 
-# Populate the namespace mapping
-from pkg_resources import resource_filename
 
+# Populate the namespace mapping
 for _ in util.find_with_extension(resource_filename(__name__, schema.NS_SCHEMA_DIR),
                                   'json'):
     schema.add_namespace(_)
 
 # Populate local namespaces
-import os
 
 try:
     for _ in util.find_with_extension(os.environ['JAMS_SCHEMA_DIR'], 'json'):