I created a class in python 2.7. Then I created a subclass of the class that I had created. For defining the init of the subclass, I used the super function, but when I ran it on python, it gave an error message:  class B:     def __init__(self, l):        self.p = l        self.d = len(l) class C(B):     def __init__(self, l):        super(C,self).__init__(l)   When I ran C(l) for some variable l, which i had entered, it showed an error message as shown below:  Traceback (most recent call last): File "&lt;stdin&gt;", line 1, in &lt;module&gt; File "class_sample.py", line 12, in __init__ super(C,self).__init__(l) TypeError: must be type, not classobj &gt;&gt;&gt;
In Python 2.5, the following code raises a TypeError:  &gt;&gt;&gt; class X:       def a(self):         print "a"  &gt;&gt;&gt; class Y(X):       def a(self):         super(Y,self).a()         print "b"  &gt;&gt;&gt; c = Y() &gt;&gt;&gt; c.a() Traceback (most recent call last):   File "&lt;stdin&gt;", line 1, in &lt;module&gt;   File "&lt;stdin&gt;", line 3, in a TypeError: super() argument 1 must be type, not classobj   If I replace the class X with class X(object), it will work. What's the explanation for this?
I do have a longer paper. In one chapter I got several multiline equations, which I wrote using the align environment from amsmath-package. Actually those are quite long computations which should break anywhere for avoiding to much empty space on a page.  I want to use something like \allowdisplaybreaks, which does exactly what I want. The problem is, that I do not want to allow displaybreaks anywhere else in the document, where I have no control about it. I tried to use \allowdisplaybreaks directly before \begin{align}, hoping it would only apply on the next following align-enviroment. But it applies to every align-environment later in the text.  Is there any way to "stop" the command again?  And yes, I could use \displaybreak for single breaks, but I had to use it in many equations and I needed to put it in every single line, since the pagebreak should move, if I add a few more lines anywhere in the chapter.   Thanks for your help, Greyfox If $H$ has maximum vertex degree at most $3$ and is a minor of $G$, then $H$ is a topological minor of $G$. If  $H$ has maximum vertex degree at most $3$ (so $\Delta(H)\leq 3$) and $H$ is a minor of $G$, then $H$ is a topological minor of $G$.   The converse follows by definition. However, most sources state this proposition without a proof. Any help is greatly appreciated. Find $\sum\limits_{k\, \text{ odd}} \frac{2(k^2-1)}{k^4+k^2+1}$ Check for internet connection with Swift Is it possible to have an ASP.NET MVC route that uses subdomain information to determine its route?  For example:   user1.domain.com goes to one place user2.domain.com goes to another?   Or, can I make it so both of these go to the same controller/action with a username parameter? Is it true that $\lfloor\sqrt{n}+\sqrt{n+1}+\sqrt{n+2} \rfloor=\lfloor\sqrt{9n+7}\rfloor$? I know it's true that  $$\lfloor\sqrt{n}+\sqrt{n+1} \rfloor=\lfloor\sqrt{4n+1}\rfloor,\forall n\in \mathbb N. \tag 1$$ Is it true that  $$\left[\sqrt{n}+\sqrt{n+1}+\sqrt{n+2} \right ]=\left[\sqrt{9n+7}\right], \tag 2$$ $$\left[\sqrt{n} +\sqrt{n+1}+\sqrt{n+2}+\sqrt{n+3}\right ]=\left[\sqrt{16n+20}\right], \tag 3$$ $$\left[\sqrt{n} +\sqrt{n+1}+\sqrt{n+2}+\sqrt{n+3}+\sqrt{n+4}\right ]=\left[\sqrt{25n+49}\right], \tag 4$$ for all $n\in \mathbb N$? I have checked $(2),(3),(4)$ through $10^6.$   (I think $(4)$ maybe has counter-examples, but I cannot find it.) NSInvalidUnarchiveOperationException: Could not instantiate class named NSLayoutConstraint How do I remove an alias? I want to remove gs alias from my PC. When I type gs it will open GhostScript. But I checked everywhere in the home directory .alias  .bash_aliases .bashrc  I also overwrite the gs with my custom alias.   I can't remove it. And I also type alias in terminal, in the list I couldn't find it.   Please I want to remove it... Convert integer to hexadecimal and back again Are there any programs that will let me dictate (speech-to-text) to any program? Or at least to a text editor and text fields in Firefox.  I’m not interested in anything that uses an online service, it has to be on-device. It may be a commercial product. How can I find the program I'm hiding in bash Say I have PATH="home/bob/bin:/usr/bin".  I am writing a bash script /home/bob/bin/foo that will do some munging and then call /usr/bin/foo.  Of course I want to be able to use this script on different systems which have different path structures.  In practice the real foo might be in many different places, so I want to just find it from the PATH.  My new foo script is on my path too, so I can't just call foo, that will result in a recursive call.  Is there an easy way of doing this in a bash script? (Other than looping through elements of PATH and doing the search manually?) Pros and cons of AppSettings vs applicationSettings (.NET app.config / Web.config) When developing a .NET Windows Forms Application we have the choice between those App.config tags to store our configuration values. Which one is better?  &lt;configuration&gt;    &lt;!-- Choice 1 --&gt;   &lt;appSettings&gt;     &lt;add key="RequestTimeoutInMilliseconds" value="10000"/&gt;   &lt;/appSettings&gt;    &lt;!-- Choice 2 --&gt;   &lt;configSections&gt;     &lt;sectionGroup name="applicationSettings" type="System.Configuration.ApplicationSettingsGroup, System, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c5612342342" &gt;         &lt;section name="Project1.Properties.Settings" type="System.Configuration.ClientSettingsSection, System, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c5612342342" requirePermission="false" /&gt;     &lt;/sectionGroup&gt;   &lt;/configSections&gt;   &lt;applicationSettings&gt;     &lt;Project1.Properties.Settings&gt;       &lt;setting name="TABLEA" serializeAs="String"&gt;         &lt;value&gt;TABLEA&lt;/value&gt;       &lt;/setting&gt;     &lt;/Project1.Properties.Settings&gt;   &lt;/applicationSettings&gt;  &lt;/configuration&gt; In the sentence: "I didn't know she had a son,"   Can I say "I didn't know she has a son" instead, because he is a teenager now?  Or are both correct? How to set the font for a \section title (and chapter etc) How do I specify the fonts, and general font size, for the titles, chapters and sections in my document  Update:  I can see how my question is confusing.  I use \section and \chapter etc. to organise my document, and I would like to change the way the section and chapter titles are displayed. Why the switch statement cannot be applied on strings? Compiling the following code and got the error of type illegal.  int main() {     // Compilation error - switch expression of type illegal     switch(std::string("raj"))     {     case"sda":     } }   You cannot use string in either switch or case. Why? Is there any solution that works nicely to support logic similar to switch on strings? Delete from uitableview + write to plist not working I know Blender is free software and bugs happen. But my question is, is it good practice to update Blender every time there is an update? Even if a minor one? (i.e I'd consider 2.56 to 2.56b minor or even 2.63, no?)  I haven't been updating very often for fear that updating frequently causes issues like broken settings, non-compatibility or lost user configs?  Or is updating often recommended to keep up to date and adapted to the new changes, i.e like upgrades in the GUI and functionality? What Happens When A Gravitational Wave Interacts With Another One? If two gravitational waves came in contact with each other what would happen? In another question entirely, what happens when a higher gravitational field interacts with a weaker one. Is save data from previous Dragon Age games used in Inquisition? Does Dragon Age Inquisition make use of save data from previous games in the series?  If so, what benefits does this provide? Let $A \subset B$ be a finite ring extension. Fix a ring homomorphism $\nu : A \to \Omega$, where $\Omega$ is an algebraically closed field.   I want to show there exists a non-zero homomorphism $v : B \to \Omega$ of $A$-modules.  I want show that the space $V$ of all the homomorphisms $v$ in (i) is a non-zero finite dimensional vector space over $\Omega$. Show that the algebra $B$ acts on this space. Show that eigenvectors of this action correspond to homomorphisms of algebras $\lambda : B \to \Omega$ that extend the homomorphism $\nu$. Deduce that the set of such homomorphisms $\lambda : B \to \Omega$ is finite and non-empty.    We can assume that $B = Ab_1 + ... + Ab_n$ where $b_1,...,b_n \in B$. The chose $v(b_i)=\omega_i \in \Omega-\{0\}$ and then define $$ v( a_1 b_1 + ... + a_n b_n ) = \nu(a_1) v(b_1) + ... + \nu(a_n) v_n = \nu(a_1) \omega_1 + ... + \nu(a_n) \omega_n \ .$$ This is an $A$-module homomorphism. Am I correct? For the second part, that $V$ is not-zero follows from the first part. That it is finite dimensional follows from the fact that $v_i(b_j)=\delta_{i,j}$ (Kronecker's delta) with $i=1,...,n$ spans $V$ and hence $\dim V \le n &lt; \infty$. I define the action of $B$ over $V$ to be $$b \bullet v = \left( x \mapsto v(b)v(x) \right) \mbox{  for all } b,x \in B \ .$$ This seems to be the natural action to define. Am I correct? However, I haven't managed to solved the rest (the eigenvector stuff and the relation to $\nu$).