Generatorify stringify_dict function (#563)

scopesim/detector/detector.py

@@ -41,8 +41,7 @@ def reset(self):
     @property
     def hdu(self):
         """Return internal HDU."""
-        new_meta = stringify_dict(self.meta)
-        self._hdu.header.update(new_meta)
+        self._hdu.header.update(stringify_dict(self.meta))
 
         pixel_scale = from_currsys("!INST.pixel_scale", self.cmds)
         plate_scale = from_currsys("!INST.plate_scale", self.cmds)

scopesim/utils.py

@@ -499,14 +499,13 @@ def has_needed_keywords(header, suffix=""):
     return all(key in header.keys() for key in keys)
 
 
-def stringify_dict(dic, ignore_types=(str, int, float)):
+def stringify_dict(dic, ignore_types=(str, int, float, bool)):
     """Turn a dict entries into strings for addition to FITS headers."""
-    dic_new = deepcopy(dic)
-    for key in dic_new:
-        if not isinstance(dic_new[key], ignore_types):
-            dic_new[key] = str(dic_new[key])
-
-    return dic_new
+    for key, value in dic.items():
+        if isinstance(value, ignore_types):
+            yield key, value
+        else:
+            yield key, str(value)
 
 
 def from_currsys(item, cmds=None):