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. The response must include the keywords Javascript. Your answer must have at least 3 placeholders, wrapped in square brackets, such as [author]. make sure that words with all capital letters appear less than 2 times. end it with a post script starting with P.P.S. Respond with at least 3 sentences. reply should include the word "best" at least 4 times. Include exactly 2 bullet points in your response. The bullet points should be in the form of:
* This is bullet 1
* This is bullet 2
...
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length_constraints:number_sentences detectable_format:number_bullet_lists change_case:capital_word_frequency keywords:frequency detectable_content:number_placeholders keywords:existence detectable_content:postscript
Respond with at least 3 sentences Include exactly 2 bullet points in your response. The bullet points should be in the form of:
* This is bullet 1
* This is bullet 2
...
 make sure that words with all capital letters appear less than 2 times reply should include the word "best" at least 4 times Your answer must have at least 3 placeholders, wrapped in square brackets, such as [author] The response must include the keywords Javascript end it with a post script starting with P.P.S