Update nipype/interfaces/io.py

Co-Authored-By: Chris Markiewicz <[email protected]>

Author: stilley2

nipype/interfaces/io.py

@@ -2867,7 +2867,7 @@ def _add_output_traits(self, base):
 
 
 class ExportFileInputSpec(BaseInterfaceInputSpec):
-    in_file = File(exists=True, desc='Input file name')
+    in_file = File(exists=True, mandatory=True, desc='Input file name')
     out_file = File(exists=False, desc='Output file name')
     check_extension = traits.Bool(False, desc='Ensure that the input and output file extensions match')
     clobber = traits.Bool(desc='Permit overwriting existing files')