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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 copy_file_links(self, src):
        # type: (RockRidge) -> None
        '''
        Copy the number of file links from the source Rock Ridge entry into
        this Rock Ridge entry.

        Parameters:
         src - The source Rock Ridge entry to copy from.
        Returns:
         Nothing.
        '''
        if not self._initialized:
            raise pycdlibexception.PyCdlibInternalError('Rock Ridge extension not yet initialized')

        # First, get the src data
        if src.dr_entries.px_record is None:
            if src.ce_entries.px_record is None:
                raise pycdlibexception.PyCdlibInvalidInput('No Rock Ridge file links')
            num_links = src.ce_entries.px_record.posix_file_links
        else:
            num_links = src.dr_entries.px_record.posix_file_links

        # Now apply it to this record.
        if self.dr_entries.px_record is None:
            if self.ce_entries.px_record is None:
                raise pycdlibexception.PyCdlibInvalidInput('No Rock Ridge file links')
            self.ce_entries.px_record.posix_file_links = num_links
        else:
            self.dr_entries.px_record.posix_file_links = num_links