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. Respond with less than 4 words be in all capital letters. Make sure to include at least 3 sections marking the beginning of each section with 'Section X'. The letter e should show up less than 5 times. The response must include the keywords heart. Write exactly 2 paragraphs each separated with two new lines answering this instruction. The first paragraph must start with "falling". make sure it contains at least 1 placeholders represented by square brackets, such as [name]. Do not include the keywords: falling.
length_constraints:nth_paragraph_first_word keywords:letter_frequency change_case:capital_word_frequency detectable_format:multiple_sections keywords:forbidden_words keywords:existence detectable_content:number_placeholders
Write exactly 2 paragraphs each separated with two new lines answering this instruction. The first paragraph must start with "falling" The letter e should show up less than 5 times Respond with less than 4 words be in all capital letters Make sure to include at least 3 sections marking the beginning of each section with 'Section X' Do not include the keywords: falling The response must include the keywords heart make sure it contains at least 1 placeholders represented by square brackets, such as [name]