chore: improve the error message when CLI control

news/improve-error-msg.rst

@@ -0,0 +1,23 @@
+**Added:**
+
+* <news item>
+
+**Changed:**
+
+* Improved the error message of `extract()` when user has issue in CLI control
+
+**Deprecated:**
+
+* <news item>
+
+**Removed:**
+
+* <news item>
+
+**Fixed:**
+
+* <news item>
+
+**Security:**
+
+* <news item>

src/diffpy/srmise/applications/extract.py

@@ -451,15 +451,31 @@ def main():
             options.peakfunction = eval("peaks." + options.peakfunction)
         except Exception as err:
             print(err)
-            print("Could not create peak function '%s'. Exiting." % options.peakfunction)
+            print(
+                f"Could not create peak function {options.peakfunction}. Exiting. "
+                f"Make sure you create peak function properly and put a pair of quote "
+                f"for the peakfunction object. "
+                f"eg: "
+                "GaussianOverR(0.7)"
+                "TerminationRipples(pf1, 20.0)"
+                ""
+            )
             return
 
     if options.modelevaluator:
         try:
             options.modelevaluator = eval("modelevaluators." + options.modelevaluator)
         except Exception as err:
             print(err)
-            print("Could not find ModelEvaluator '%s'. Exiting." % options.modelevaluator)
+            print(
+                f"Could not find ModelEvaluator {options.modelevaluator}. Exiting."
+                f"Make sure you create ModelEvaluator properly and put a pair of quote "
+                f"for the modeevaluator object. "
+                f"eg: "
+                "AIC"
+                "AICc"
+                ""
+            )
             return
 
     if options.bcrystal:
@@ -507,7 +523,14 @@ def main():
             )
         except Exception as err:
             print(err)
-            print("Could not create baseline '%s'. Exiting." % options.baseline)
+            print(
+                f"Could not create baseline {options.baseline}. Exiting."
+                f"Make sure you create baseline properly and put a pair of quote for the baseline."
+                f"eg: "
+                "Polynomial(degree=1)"
+                "NanoSpherical()"
+                ""
+            )
             return
 
     filename = args[0]