pycharm 运行时执行了两次

RT，PyCharm版本号是Community Edition 2017.2.4 https://wx2.sinaimg.cn/mw690/62f40e5bgy1fmnnbkf91ij20qn0goqmj.jpg

以下是脚本

# coding: utf-8
import numpy as np
import pandas as pd
from tempfile import NamedTemporaryFile

np.random.seed(42)
a = np.random.randn(365, 4)

# tmpf = NamedTemporaryFile()
tmpf = './data/t.csv'
store = pd.io.pytables.HDFStore(tmpf)
print store

df = pd.DataFrame(a)
store['df'] = df
print store

print "Get", store.get('df').shape
print "Lookup", store['df'].shape
print "Dotted", store.df.shape

del store['df']
print "After del\n", store

print "Before close", store.is_open
store.close()
print "After close", store.is_open

df.to_hdf(tmpf, 'data', format='table')
print pd.read_hdf(tmpf, 'data', where=['index>363'])

以下是运行的结果，之前还只是以为重复打印。刚开始t.csv文件是不存在的，所以 HDFStore 的结果是Empty。但是查看运行结果发现第二次的文件结果不为空，由此可以程序又运行了一次。

# 第一次运行
C:\APPS\Anaconda\python.exe D:/DATA/DEV/python/py.py
<class 'pandas.io.pytables.HDFStore'>
File path: ./data/t.csv
Empty    #结果为空
<class 'pandas.io.pytables.HDFStore'>
File path: ./data/t.csv
/df            frame        (shape->[365,4])
Get (365, 4)
Lookup (365, 4)
Dotted (365, 4)
After del
<class 'pandas.io.pytables.HDFStore'>
File path: ./data/t.csv
Empty
Before close True
After close False
            0         1         2         3
364  0.753342  0.381158  1.289753  0.673181
# 第二次运行
<class 'pandas.io.pytables.HDFStore'>
File path: ./data/t.csv
# 文件结果不为空，由此可以程序又运行了一次
/data            frame_table  (typ->appendable,nrows->365,ncols->4,indexers->[index]) 
<class 'pandas.io.pytables.HDFStore'>
File path: ./data/t.csv
/data            frame_table  (typ->appendable,nrows->365,ncols->4,indexers->[index])
/df              frame        (shape->[365,4])                                       
Get (365, 4)
Lookup (365, 4)
Dotted (365, 4)
After del
<class 'pandas.io.pytables.HDFStore'>
File path: ./data/t.csv
/data            frame_table  (typ->appendable,nrows->365,ncols->4,indexers->[index])
Before close True
After close False
            0         1         2         3
364  0.753342  0.381158  1.289753  0.673181

Process finished with exit code 0

请问是什么原因？