class_docstr: A reference frame in classical mechanics.
  
  ReferenceFrame is a class used to represent a reference frame in classical
  mechanics. It has a standard basis of three unit vectors in the frame's
  x, y, and z directions.
  
  It also can have a rotation relative to a parent frame; this rotation is
  defined by a direction cosine matrix relating this frame's basis vectors to
  the parent frame's basis vectors.  It can also have an angular velocity
  vector, defined in another frame.
docstr: Returns the angular acceleration Vector of the ReferenceFrame.
  
  Effectively returns the Vector:
  
  ``N_alpha_B``
  
  which represent the angular acceleration of B in N, where B is self,
  and N is otherframe.
  
  Parameters
  ==========
  
  otherframe : ReferenceFrame
      The ReferenceFrame which the angular acceleration is returned in.
  
  Examples
  ========
  
  >>> from sympy.physics.vector import ReferenceFrame
  >>> N = ReferenceFrame('N')
  >>> A = ReferenceFrame('A')
  >>> V = 10 * N.x
  >>> A.set_ang_acc(N, V)
  >>> A.ang_acc_in(N)
  10*N.x
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code: def ang_acc_in(self, otherframe):
      """Returns the angular acceleration Vector of the ReferenceFrame.
  
      Effectively returns the Vector:
  
      ``N_alpha_B``
  
      which represent the angular acceleration of B in N, where B is self,
      and N is otherframe.
  
      Parameters
      ==========
  
      otherframe : ReferenceFrame
          The ReferenceFrame which the angular acceleration is returned in.
  
      Examples
      ========
  
      >>> from sympy.physics.vector import ReferenceFrame
      >>> N = ReferenceFrame('N')
      >>> A = ReferenceFrame('A')
      >>> V = 10 * N.x
      >>> A.set_ang_acc(N, V)
      >>> A.ang_acc_in(N)
      10*N.x
  
      """
  
      _check_frame(otherframe)
      if otherframe in self._ang_acc_dict:
          return self._ang_acc_dict[otherframe]
      else:
          return self.ang_vel_in(otherframe).dt(otherframe)
  
imports: from sympy import diff, expand, sin, cos, sympify, eye, zeros, ImmutableMatrix, MatrixBase
  from sympy.core.symbol import Symbol
  from sympy.simplify.trigsimp import trigsimp
  from sympy.physics.vector.vector import Vector, _check_vector
  from sympy.utilities.misc import translate
  from warnings import warn
label_desc: Use image node_id 8 for calling the ReferenceFrame obj's underlying member method code with example usage: obj.ang_acc_in(otherframe) and returns: self, self