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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_all():
 """Return a list of all PDB entries currently in the RCSB Protein Data Bank Returns ------- out : list of str A list of all of the PDB IDs currently in the RCSB PDB Examples -------- ['100D', '101D', '101M', '102D', '102L', '102M', '103D', '103L', '103M', '104D'] """


    url = 'http://www.rcsb.org/pdb/rest/getCurrent'

    req = urllib.request.Request(url)
    f = urllib.request.urlopen(req)
    result = f.read()
    assert result

    kk = str(result)

    p = re.compile('structureId=\"...."')
    matches = p.findall(str(result))
    out = list()
    for item in matches:
        out.append(item[-5:-1])

    return out