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