Relocate EMPTY_BYTE_STRING constant from portability to util.

segpy/portability.py

@@ -1,4 +0,0 @@
-import os
-import sys
-
-EMPTY_BYTE_STRING = b'' if sys.version_info >= (3, 0) else ''

segpy/toolkit.py

@@ -18,8 +18,8 @@ from segpy.ibm_float import IBMFloat
 from segpy.packer import HeaderPacker
 from segpy.revisions import canonicalize_revision
 from segpy.trace_header import TraceHeaderRev1
-from segpy.util import file_length, batched, pad, complementary_intervals, NATIVE_ENDIANNESS
-from segpy.portability import EMPTY_BYTE_STRING
+from segpy.util import file_length, batched, pad, complementary_intervals, NATIVE_ENDIANNESS, EMPTY_BYTE_STRING
+
 
 HEADER_NEWLINE = '\r\n'
 

segpy/util.py

@@ -7,6 +7,8 @@ from itertools import (islice, cycle, tee, chain, repeat)
 
 NATIVE_ENDIANNESS = '<' if sys.byteorder == 'little' else '>'
 
+EMPTY_BYTE_STRING = b''
+
 UNSET = object()
 
 def pairwise(iterable):