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.
detectable_content:postscript change_case:capital_word_frequency detectable_content:number_placeholders length_constraints:number_sentences language:response_language startend:quotation punctuation:no_comma
P.P.S
at least
less than
ta
please explicitly add a note starting with P.P.S Use words in all capital letters at least 1 times The response must contain at least 2 placeholders represented by square brackets Please make sure the response less than 3 sentences long Please respond to me only in Tamil You need to wrap your entire response in double quotes In your response please avoid using commas