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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def open(filename, mode = 'r', iline = 189, xline = 193, strict = True, ignore_geometry = False, endian = 'big' ):
 """Open a seismic unix file. Behaves identically to open(), except it expects the seismic unix format, not SEG-Y. Parameters filename : str Path to file to open mode : {'r', 'r+'} File access mode, read-only ('r', default) or read-write ('r+') iline : int or segyio.TraceField Inline number field in the trace headers. Defaults to 189 as per the SEG-Y rev1 specification xline : int or segyio.TraceField Crossline number field in the trace headers. Defaults to 193 as per the SEG-Y rev1 specification strict : bool, optional Abort if a geometry cannot be inferred. Defaults to True. ignore_geometry : bool, optional Opt out on building geometry information, useful for e.g. shot organised files. Defaults to False. endian : {'big', 'msb', 'little', 'lsb'} File endianness, big/msb (default) or little/lsb Returns ------- file : segyio.su.file An open seismic unix file handle Raises ------ ValueError If the mode string contains 'w', as it would truncate the file See also -------- segyio.open : SEG-Y open Notes ----- .. versionadded:: 1.8 """


    if 'w' in mode:
        problem = 'w in mode would truncate the file'
        solution = 'use r+ to open in read-write'
        raise ValueError(', '.join((problem, solution)))

    endians = {
        'little': 256, # (1 << 8)
        'lsb': 256,
        'big': 0,
        'msb': 0,
    }

    if endian not in endians:
        problem = 'unknown endianness, must be one of: '
        candidates = ' '.join(endians.keys())
        raise ValueError(problem + candidates)

    from .. import _segyio
    fd = _segyio.segyiofd(str(filename), mode, endians[endian])
    fd.suopen()
    metrics = fd.metrics()

    f = sufile(
        fd,
        filename = str(filename),
        mode = mode,
        iline = iline,
        xline = xline,
    )

    h0 = f.header[0]

    dt = h0[words.dt] / 1000.0
    t0 = h0[words.delrt]
    samples = metrics['samplecount']
    f._samples = (numpy.arange(samples) * dt) + t0

    if ignore_geometry:
        return f

    return infer_geometry(f, metrics, iline, xline, strict)