code: def _distribution(gtfs, table, column):
      
      cur = gtfs.conn.cursor()
      cur.execute('SELECT {column}, count(*) '
                  'FROM {table} GROUP BY {column} '
                  'ORDER BY {column}'.format(column=column, table=table))
      return ' '.join('%s:%s' % (t, c) for t, c in cur)
docs: Count occurrences of values AND return it as a string.
  
      Example return value:   '1:5 2:15