Grid/GridRegistry.php
public function addColumn(Column $column)
    {
        $type = $column->getType();

        if ($this->hasColumn($type)) {
            throw new ColumnAlreadyExistsException($type);
        }

        $this->columns[$type] = $column;

        return $this;
    }
public function addColumn(Column $column)
    {
        $type = $column->getType();

        if ($this->hasColumn($type)) {
            throw new ColumnAlreadyExistsException($type);
        }

        $this->columns[$type] = $column;

        return $this;
    }
Add a column type.

@param Column $column

@return $this