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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 save_to_file(self, filename, remap_dim0=None, remap_dim1=None):
 """Saves matrix to the file. Args: filename: name of the file where to save matrix remap_dim0: dictionary with mapping row indices to row names which should be saved to file. If none then indices will be used as names. remap_dim1: dictionary with mapping column indices to column names which should be saved to file. If none then indices will be used as names. """

    # rows - first index
    # columns - second index
    with open(filename, 'w') as fobj:
      columns = list(sorted(self._dim1))
      for col in columns:
        fobj.write(',')
        fobj.write(str(remap_dim1[col] if remap_dim1 else col))
      fobj.write('\n')
      for row in sorted(self._dim0):
        fobj.write(str(remap_dim0[row] if remap_dim0 else row))
        for col in columns:
          fobj.write(',')
          fobj.write(str(self[row, col]))
        fobj.write('\n')