PEP8 + addressed's @matthew-brett's comments

Author: MarcCote

nibabel/streamlines/tck.py

@@ -7,7 +7,6 @@
 
 import os
 import warnings
-from collections import OrderedDict
 
 import numpy as np
 
@@ -25,7 +24,7 @@
 
 def create_empty_header():
     ''' Return an empty compliant TCK header. '''
-    header = OrderedDict()
+    header = {}
 
     # Default values
     header[Field.MAGIC_NUMBER] = TckFile.MAGIC_NUMBER
@@ -45,14 +44,14 @@ class TckFile(TractogramFile):
 
     Moreover, streamlines coordinates coming from a TCK file are considered
     to be in world space (RAS+ and mm space). MRtrix refers to that space
-    as the "real" or "scanner" space _[1].
+    as the "real" or "scanner" space [1]_.
 
     References
     ----------
     [1] http://www.nitrc.org/pipermail/mrtrix-discussion/2014-January/000859.html
     """
 
-    # Contants
+    # Constants
     MAGIC_NUMBER = "mrtrix tracks"
     SUPPORTS_DATA_PER_POINT = False  # Not yet
     SUPPORTS_DATA_PER_STREAMLINE = False  # Not yet
@@ -66,8 +65,9 @@ def __init__(self, tractogram, header=None):
         ----------
         tractogram : :class:`Tractogram` object
             Tractogram that will be contained in this :class:`TckFile`.
-        header : dict (optional)
-            Metadata associated to this tractogram file.
+        header : None or dict, optional
+            Metadata associated to this tractogram file. If None, make
+            default empty header.
 
         Notes
         -----
@@ -214,7 +214,7 @@ def save(self, fileobj):
             for t in tractogram:
                 s = t.streamline.astype(dtype)
                 data = np.r_[s, self.FIBER_DELIMITER]
-                f.write(asbytes(data.tostring()))
+                f.write(data.tostring())
                 nb_streamlines += 1
 
             header[Field.NB_STREAMLINES] = nb_streamlines
@@ -283,7 +283,7 @@ def _read_header(fileobj):
         Parameters
         ----------
         fileobj : string or file-like object
-            If string, a filename; otherwise an open file-like object
+            If string, a filename; otherwise an open binary file-like object
             pointing to TCK file (and ready to read from the beginning
             of the TCK header). Note that calling this function
             does not change the file position.

nibabel/streamlines/tests/test_streamlines.py

@@ -246,11 +246,9 @@ def test_save_complex_file(self):
                     # If streamlines format does not support saving data
                     # per point or data per streamline, warning messages
                     # should be issued.
-                    nb_expected_warnings = 0
-                    if not cls.SUPPORTS_DATA_PER_POINT:
-                        nb_expected_warnings += 1
-                    if not cls.SUPPORTS_DATA_PER_STREAMLINE:
-                        nb_expected_warnings += 1
+                    nb_expected_warnings = \
+                        ((not cls.SUPPORTS_DATA_PER_POINT) +
+                         (not cls.SUPPORTS_DATA_PER_STREAMLINE))
 
                     assert_equal(len(w), nb_expected_warnings)
                     for i in range(nb_expected_warnings):

nibabel/streamlines/tests/test_tck.py

@@ -31,9 +31,9 @@ def setup():
     # standard.tck contains only streamlines
     DATA['standard_tck_fname'] = pjoin(data_path, "standard.tck")
 
-    DATA['streamlines'] = [np.arange(1*3, dtype="f4").reshape((1, 3)),
-                           np.arange(2*3, dtype="f4").reshape((2, 3)),
-                           np.arange(5*3, dtype="f4").reshape((5, 3))]
+    DATA['streamlines'] = [np.arange(1 * 3, dtype="f4").reshape((1, 3)),
+                           np.arange(2 * 3, dtype="f4").reshape((2, 3)),
+                           np.arange(5 * 3, dtype="f4").reshape((5, 3))]
 
     DATA['empty_tractogram'] = Tractogram(affine_to_rasmm=np.eye(4))
     DATA['simple_tractogram'] = Tractogram(DATA['streamlines'],