1. Create a new column (w/ temp name and correct type)
        2. Copy data over to it
        3. Drop the existing column (cascade!)
        4. Rename the new column to existing column

def alter_column_type(self, relation, column_name, new_column_type):
        """
        1. Create a new column (w/ temp name and correct type)
        2. Copy data over to it
        3. Drop the existing column (cascade!)
        4. Rename the new column to existing column
        """
        kwargs = {
            'relation': relation,
            'column_name': column_name,
            'new_column_type': new_column_type,
        }
        self.execute_macro(
            ALTER_COLUMN_TYPE_MACRO_NAME,
            kwargs=kwargs
        )