Missed space for separator on optional array command input binding

Author: illusional

wdlgen/task.py

@@ -110,7 +110,7 @@ def get_string(self):
                     if self.optional:
                         # Ugly optional workaround: https://github.com/openwdl/wdl/issues/25#issuecomment-315424063
                         internal_pref = f'if defined({name}) then "{bc}" else ""'
-                        return f'${{{internal_pref}}}${{sep="{bc}" {name}}}'
+                        return f'${{{internal_pref}}}${{sep=" {bc}" {name}}}'
                     return f'${{sep=" " prefix("{bc}", {name})}}'
 
                 options = []