code: def insert(self, loc, column, value, allow_duplicates=False):
          
          self._ensure_valid_index(value)
          value = self._sanitize_column(column, value, broadcast=False)
          self._data.insert(loc, column, value,
                            allow_duplicates=allow_duplicates)
docs: Insert column into DataFrame at specified location.
  
          Raises a ValueError if `column` is already contained in the DataFrame,
          unless `allow_duplicates` is set to True.
  
          Parameters
          ----------
          loc : int
              Insertion index. Must verify 0 <= loc <= len(columns)
          column : string, number, or hashable object
              label of the inserted column
          value : int, Series, or array-like
          allow_duplicates : bool, optional