code: public Double getDouble(final String column) {
      int index = _headerDefinition.columnIndex(column);
      return getDouble(index);
    }
docs: Returns an entry from a given column name as a Double (possibly null). Throws an IllegalArgumentException if the name is not defined in
  the header definition. Throws a NumberFormatException if the underlying data cannot be parsed as a double precision floating point
  number.
  
  @param column the column name of the entry, not null
  @return the entry, can be null if the value is null or empty