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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 read_hlet_wcs(filename, ext):
 """Insure `stwcs.wcsutil.HSTWCS` includes all attributes of a full image WCS. For headerlets, the WCS does not contain information about the size of the image, as the image array is not present in the headerlet. """

    hstwcs = wcsutil.HSTWCS(filename, ext=ext)
    if hstwcs.naxis1 is None:
        hstwcs.naxis1 = int(hstwcs.wcs.crpix[0] * 2.)  # Assume crpix is center of chip
        hstwcs.naxis2 = int(hstwcs.wcs.crpix[1] * 2.)

    return hstwcs