def concatenate_transforms(pet_to_t1w_tranform, t1w_to_mni_tranform):
    """Concatenate two input transformation files into a list.
    Args:
       transform1 (str): first transformation to apply
       transform2 (str): second transformation to apply
    Returns:
       transform_list (list of string): both transform files path in a list
    """
    return [t1w_to_mni_tranform, pet_to_t1w_tranform]