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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 WriteScanContext(self, scan_context, scan_step=None):
 """Writes the source scanner context to stdout. Args: scan_context (SourceScannerContext):
 the source scanner context. scan_step (Optional[int]):
 the scan step, where None represents no step. """

    if scan_step is not None:
      print('Scan step: {0:d}'.format(scan_step))

    print('Source type\t\t: {0:s}'.format(scan_context.source_type))
    print('')

    scan_node = scan_context.GetRootScanNode()
    self.WriteScanNode(scan_context, scan_node)
    print('')