Write out the definition of the function 'sum_numbers'
sum_numbers is a function that takes in a list or an array of numbers as its parameters and returns the total sum of all the numbers in the list or array. The function iterates through each element in the input and adds their values to an accumulator variable which is then returned as the final result of the function.
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Below is an instruction that describes a task, paired with an input that provides further context. Write a response that appropriately completes the request.

### Instruction:
Write out the definition of the function 'sum_numbers'

### Input:
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### Response:
sum_numbers is a function that takes in a list or an array of numbers as its parameters and returns the total sum of all the numbers in the list or array. The function iterates through each element in the input and adds their values to an accumulator variable which is then returned as the final result of the function.