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