class_docstr: This class wraps data into a dict-like object
docstr: Return a DataAccessObject containing the first n rows
  
  :param n: number of rows
  :return: DataAccessObject
docstr_tok: ["Return","a","DataAccessObject","containing","the","first","n","rows",":","param","n",":","number","of","rows",":","return",":","DataAccessObject"]
code: def head(self, n):
      """
      Return a DataAccessObject containing the first n rows
  
      :param n: number of rows
      :return: DataAccessObject
      """
      return DataAccessObject({k: self.dict[k][:n] for k in self.dict})
  
imports: from collections import defaultdict
  import csv
  from datetime import datetime
  import json
  from math import radians, cos, sin, asin, sqrt
  import urllib2
  import numpy
label_desc: Use image node_id 9 for calling the DataAccessObject obj's underlying member method code with example usage: obj.head(n) and returns: DataAccessObject