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_format:number_highlighted_sections length_constraints:nth_paragraph_first_word length_constraints:number_sentences keywords:letter_frequency language:response_language length_constraints:number_words detectable_format:number_bullet_lists
art
less than
at least
l
sw
less than
Make sure to highlight at least 1 sections in your answer with markdown, i.e. use *highlighted section* Response should contain exactly 2 paragraphs, and the first paragraph must start with the word "art". Separate paragraphs by double line breaks ("\n\n") Respond with less than 5 sentences In your entire response, the letter l should appear at least 3 times Please respond to me only in Swahili Keep your entire response less than 65 words or less. Your answer must be in the form of exactly 2 bullet points with the format below:
* This is bullet point 1
* This is bullet point 2