Write a Python program that takes a list of numbers as input from the user, calculates the sum of all even numbers in the list, and returns the result. The program should check if the input is valid (i.e., if it's a list of numbers), and if it's not, it should return an error message. The program should also handle exceptions gracefully and return a user-friendly error message in case of any exceptions. end it with a post script starting with P.P.S. Your answer must have at least 3 placeholders, wrapped in square brackets, such as [author]. Include exactly 2 bullet points in your response. The bullet points should be in the form of:
* This is bullet 1
* This is bullet 2
...
. The response must include the keywords Javascript. reply should include the word "best" at least 4 times. make sure that words with all capital letters appear less than 2 times. Respond with at least 3 sentences.
length_constraints:number_sentences change_case:capital_word_frequency keywords:frequency keywords:existence detectable_format:number_bullet_lists detectable_content:number_placeholders detectable_content:postscript
Respond with at least 3 sentences make sure that words with all capital letters appear less than 2 times reply should include the word "best" at least 4 times The response must include the keywords Javascript Include exactly 2 bullet points in your response. The bullet points should be in the form of:
* This is bullet 1
* This is bullet 2
...
 Your answer must have at least 3 placeholders, wrapped in square brackets, such as [author] end it with a post script starting with P.P.S