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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 errch(marker, string):
 """ Substitute a character string for the first occurrence of a marker in the current long error message. http://naif.jpl.nasa.gov/pub/naif/toolkit_docs/C/cspice/errch_c.html :param marker: A substring of the error message to be replaced. :type marker: str :param string: The character string to substitute for marker. :type string: str """

    marker = stypes.stringToCharP(marker)
    string = stypes.stringToCharP(string)
    libspice.errch_c(marker, string)