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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 createDocParserCtxt(cur):
 """Creates a parser context for an XML in-memory document. """

    ret = libxml2mod.xmlCreateDocParserCtxt(cur)
    if ret is None:raise parserError('xmlCreateDocParserCtxt() failed')
    return parserCtxt(_obj=ret)