cmath.atan(x) Return the arc tangent of x. There are two branch cuts: One extends from 1j along the imaginary axis to ∞j, continuous from the right. The other extends from -1j along the imaginary axis to -∞j, continuous from the left.

classmethod(function) Return a class method for function. A class method receives the class as implicit first argument, just like an instance method receives the instance. To declare a class method, use this idiom: class C: @classmethod def f(cls, arg1, arg2, ...): ... The @classmethod form is a function decorator – see the description of function definitions in Function definitions for details. It can be called either on the class (such as C.f()) or on an instance (such as C().f())

class.__subclasses__() Each class keeps a list of weak references to its immediate subclasses. This method returns a list of all those references still alive. Example: >>> int.__subclasses__() [<class 'bool'>]

class.__mro__ This attribute is a tuple of classes that are considered when looking for base classes during method resolution.

class.mro() This method can be overridden by a metaclass to customize the method resolution order for its instances. It is called at class instantiation, and its result is stored in __mro__.

class.__bases__ The tuple of base classes of a class object.

tell() Return the current position into the chunk.

isatty() Returns False.

seek(pos, whence=0) Set the chunk’s current position. The whence argument is optional and defaults to 0 (absolute file positioning); other values are 1 (seek relative to the current position) and 2 (seek relative to the file’s end). There is no return value. If the underlying file does not allow seek, only forward seeks are allowed.

skip() Skip to the end of the chunk. All further calls to read() for the chunk will return b''. If you are not interested in the contents of the chunk, this method should be called so that the file points to the start of the next chunk.