class_docstr: Enumeration of types of musculotendon dynamics formulations.
  
  Explanation
  ===========
  
  An (integer) enumeration is used as it allows for clearer selection of the
  different formulations of musculotendon dynamics.
  
  Members
  =======
  
  RIGID_TENDON : 0
      A rigid tendon model.
  FIBER_LENGTH_EXPLICIT : 1
      An explicit elastic tendon model with the muscle fiber length (l_M) as
      the state variable.
  TENDON_FORCE_EXPLICIT : 2
      An explicit elastic tendon model with the tendon force (F_T) as the
      state variable.
  FIBER_LENGTH_IMPLICIT : 3
      An implicit elastic tendon model with the muscle fiber length (l_M) as
      the state variable and the muscle fiber velocity as an additional input
      variable.
  TENDON_FORCE_IMPLICIT : 4
      An implicit elastic tendon model with the tendon force (F_T) as the
      state variable as the muscle fiber velocity as an additional input
      variable.
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docstr: Returns a string representation of the enumeration value.
  
  Notes
  =====
  
  This hard coding is required due to an incompatibility between the
  ``IntEnum`` implementations in Python 3.10 and Python 3.11
  (https://github.com/python/cpython/issues/84247). From Python 3.11
  onwards, the ``__str__`` method uses ``int.__str__``, whereas prior it
  used ``Enum.__str__``. Once Python 3.11 becomes the minimum version
  supported by SymPy, this method override can be removed.
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code: def __str__(self):
      """Returns a string representation of the enumeration value.
  
      Notes
      =====
  
      This hard coding is required due to an incompatibility between the
      ``IntEnum`` implementations in Python 3.10 and Python 3.11
      (https://github.com/python/cpython/issues/84247). From Python 3.11
      onwards, the ``__str__`` method uses ``int.__str__``, whereas prior it
      used ``Enum.__str__``. Once Python 3.11 becomes the minimum version
      supported by SymPy, this method override can be removed.
  
      """
      return str(self.value)
  
imports: from abc import abstractmethod
  from enum import IntEnum, unique
  from sympy.core.numbers import Float, Integer
  from sympy.core.symbol import Symbol, symbols
  from sympy.functions.elementary.miscellaneous import sqrt
  from sympy.functions.elementary.trigonometric import cos, sin
  from sympy.matrices.dense import MutableDenseMatrix, diag, eye, zeros
  from sympy.physics.biomechanics.activation import ActivationBase
  from sympy.physics.biomechanics.curve import CharacteristicCurveCollection, FiberForceLengthActiveDeGroote2016, FiberForceLengthPassiveDeGroote2016, FiberForceLengthPassiveInverseDeGroote2016, FiberForceVelocityDeGroote2016, FiberForceVelocityInverseDeGroote2016, TendonForceLengthDeGroote2016, TendonForceLengthInverseDeGroote2016
  from sympy.physics.biomechanics._mixin import _NamedMixin
  from sympy.physics.mechanics.actuator import ForceActuator
  from sympy.physics.vector.functions import dynamicsymbols
label_desc: Use image node_id 1 for calling the MusculotendonFormulation obj's underlying member method code with example usage: obj.__str__() and returns: str