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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 get_header(uri):
 """ Pull a FITS header from observation at the given URI @param uri: The URI of the image in VOSpace. """

    if uri not in astheaders:
        astheaders[uri] = get_hdu(uri, cutout="[1:1,1:1]")[0].header
    return astheaders[uri]