code: def merge_split_adjustments_with_overwrites(
          self,
          pre,
          post,
          overwrites,
          requested_split_adjusted_columns
      ):
          
          for column_name in requested_split_adjusted_columns:
              # We can do a merge here because the timestamps in 'pre' and
              # 'post' are guaranteed to not overlap.
              if pre:
                  # Either empty or contains all columns.
                  for ts in pre[column_name]:
                      add_new_adjustments(
                          overwrites,
                          pre[column_name][ts],
                          column_name,
                          ts
                      )
              if post:
                  # Either empty or contains all columns.
                  for ts in post[column_name]:
                      add_new_adjustments(
                          overwrites,
                          post[column_name][ts],
                          column_name,
                          ts
                      )
docs: Merge split adjustments with the dict containing overwrites.
  
          Parameters
          ----------
          pre : dict[str -> dict[int -> list]]
              The adjustments that occur before the split-adjusted-asof-date.
          post : dict[str -> dict[int -> list]]
              The adjustments that occur after the split-adjusted-asof-date.
          overwrites : dict[str -> dict[int -> list]]
              The overwrites across all time. Adjustments will be merged into
              this dictionary.
          requested_split_adjusted_columns : list of str
              List of names of split adjusted columns that are being requested.