<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def read_transform(filename, dimension=2, precision='float'):
 """ Read a transform from file ANTsR function: `readAntsrTransform` Arguments --------- filename : string filename of transform dimension : integer spatial dimension of transform precision : string numerical precision of transform Returns ------- ANTsTransform Example ------- """

    filename = os.path.expanduser(filename)
    if not os.path.exists(filename):
        raise ValueError('filename does not exist!')

    libfn1 = utils.get_lib_fn('getTransformDimensionFromFile')
    dimension = libfn1(filename)

    libfn2 = utils.get_lib_fn('getTransformNameFromFile')
    transform_type = libfn2(filename)

    libfn3 = utils.get_lib_fn('readTransform%s%i' % (utils.short_ptype(precision), dimension))
    itk_tx = libfn3(filename, dimension, precision)

    return tio.ANTsTransform(precision=precision, dimension=dimension, 
                            transform_type=transform_type, pointer=itk_tx)