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Python: source code has attributes that are unaccessible from outside of it

So i've been wondering around the other day and stumbled across this piece of code from datetime.datetime:
def timestamp(self):
"Return POSIX timestamp as float"
if self._tzinfo is None:
s = self._mktime()
return s + self.microsecond / 1e6
else:
return (self - _EPOCH).total_seconds()
I decided to check what self._tzinfo and self._mktime() are, so i ran this code in console:
>>> datetime(1970, 1, 1)._tzinfo
Traceback (most recent call last):
File "<input>", line 1, in <module>
AttributeError: 'datetime.datetime' object has no attribute '_tzinfo'
>>> datetime(1970, 1, 1)._mktime()
Traceback (most recent call last):
File "<input>", line 1, in <module>
AttributeError: 'datetime.datetime' object has no attribute '_mktime'
But to my surprise i got AttributeError on both occasions. PyCharm says Cannot find declaration to go to. Yet, there is a normal declaration of _mktime() method right above the timestamp() method.
Despite all this, of course, timestamp() works totally fine.
>>> datetime(1970, 1, 1).timestamp()
-10800.0
So why is this happening? Why are these attributes not accessible from outside and why does interpreter react to them so weirdly?

TypeError: 'float' object has no attribute '__getitem__' in Python

I am working on a project in Python. I am a beginner and I am getting this error when I am running the program.
Traceback (most recent call last):
File "E:/Python/1616/checkProfile.py", line 104, in <module>
p.getResults()
File "E:\Python\1616\Profile.py", line 67, in getResults
for i in range(2): self._s[1] += e.getS[1]
TypeError: 'float' object has no attribute '__getitem__'
Error in Line 67
http://pastebin.com/HXvppfmU

to check what are the methods allowed for datatypes,
dir(datatype)
# As for float, try dir(float)
#This will suggest you that there is no method called __getitem__ for float.
# You might be trying to get some data or you are using []/()/{} which is not correct.
Try to post ur code.

python boto 'NoneType' object has no attribute 'stop_isntances'

i am learning python boto module and i am trying to stop a running instance .
import boto.ec2
conn = boto.ec2.connect_to_region("us-west-2")
conn.stop_instances(instance_ids=['i-0aa5ce441ef7e0e2a'])
but i am getting error which says:
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
AttributeError: 'NoneType' object has no attribute 'stop_instances'
i gave AWS_access keys for boto.
can anyone please help me to fix this error ?

As #kindall points out, your conn object is not initialized (it's NoneType). I also see that you're using boto in the example, but I thought that I would provide an example of this using boto3:
import boto3
boto3_session = boto3.Session(profile=some_profile_you_configured)
boto3_client = boto3_session.client('ec2', region_name='us-west-2')
response = boto3_client.stop_instances(InstanceIds=['i-0aa5ce441ef7e0e2a'])

SQLAlchemy Error when filtering

I'm using using SQLAlchemy to fiter but getting an error:
user = session.query.filter(User.id == 99).one()
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
AttributeError: 'function' object has no attribute 'filter'
Does someone know how to filter because on SQLAlchemy Page, I saw this:
query = session.query(User).filter

query is a function, you need to pass in the User class to call it:
user = session.query(User).filter(User.id == 99).one()
^^^^^^
SQLAlchemy cannot divine from the filter alone what type of object you want returned otherwise.

storing result of MySQL query into python variable

when I execute the following code using python programming language and MySQL database
cursor.execute("select max(propernoun_SRNO) from tblauto_tagged")
starting_index = cursor.fetchone()
ending_index = starting_index +len(s)
I get following error:
Traceback (most recent call last):
File "<pyshell#0>", line 1, in <module>
batch(1,1)
File "C:\Users\vchauhan\Dropbox\Code\proper_noun_function_batch_file_mysql_sept_12.py", line 97, in batch
ending_index = starting_index +len(s)
TypeError: unsupported operand type(s) for +: 'pyodbc.Row' and 'int'

Problem
The problem here is that you are assigning pyodbc.Row instance (returned by .fetchone()) to starting_index, which makes it impossible to add it to the integer (thus the "TypeError: unsupported operand type(s)" error).
Solution
Try to replace this line:
starting_index = cursor.fetchone()
with this line:
starting_index = cursor.fetchone()[0]
More reading
PEP 249 - Python Database API Specification v2.0 (especially part about fetchone())