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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 IsErrorSuppressedByNolint(category, linenum):
 """Returns true if the specified error category is suppressed on this line. Consults the global error_suppressions map populated by ParseNolintSuppressions/ResetNolintSuppressions. Args: category: str, the category of the error. linenum: int, the current line number. Returns: bool, True iff the error should be suppressed due to a NOLINT comment. """

  return (linenum in _error_suppressions.get(category, set()) or
          linenum in _error_suppressions.get(None, set()))