def arrayCheck(nums):
    """
    Function to find a sequence 1, 2, 3.

    Given a list of integers, return True if the sequence of numbers 1, 2, 3
    appears in the list somewhere.

    Args:
        nums (Array): Array of integer
    """

    for i in range(len(nums)-2):
        if nums[i] == 1 and nums[i+1] == 2 and nums[i+2] == 3:
            return True

    return False