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. There should be exactly 4 paragraphs each separated by two new lines in your response. fourth paragraph must start with the word reduce. Your answer must contain exactly 4 bullet point in Markdown using the following format:
* Bullet point one.
* Bullet point two.
.... make sure it contains at least 1 placeholders represented by square brackets, such as [name]. Please respond to me only in Korean. Your answer need to be wrapped in double quotes. Use words in all capital letters less than 4 times. Contain less than 6 letter"y" in your response.
length_constraints:nth_paragraph_first_word keywords:letter_frequency language:response_language change_case:capital_word_frequency detectable_format:number_bullet_lists detectable_content:number_placeholders startend:quotation
There should be exactly 4 paragraphs each separated by two new lines in your response. fourth paragraph must start with the word reduce Contain less than 6 letter"y" in your response Please respond to me only in Korean Use words in all capital letters less than 4 times Your answer must contain exactly 4 bullet point in Markdown using the following format:
* Bullet point one.
* Bullet point two.
... make sure it contains at least 1 placeholders represented by square brackets, such as [name] Your answer need to be wrapped in double quotes