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