Fix bug where skip_checksum argument is incorrectly passed when creating a SigMFFile instance with a pre-exisiting data file. (#9)

Author: nwhitehair

sigmf/sigmffile.py

@@ -182,7 +182,7 @@ def __init__(self, metadata=None, data_file=None, global_info=None, skip_checksu
         if global_info is not None:
             self.set_global_info(global_info)
         if data_file is not None:
-            self.set_data_file(data_file, skip_checksum, map_readonly=map_readonly)
+            self.set_data_file(data_file, skip_checksum=skip_checksum, map_readonly=map_readonly)
 
     def __len__(self):
         return self._memmap.shape[0]