text: r"""
  Copulas are a type dependency structure imposed on independent variables to
  achieve to more complex problems without adding too much complexity.
  
  To construct a copula one needs a copula transformation and the
  Copula wrapper::
  
      >>> dist = chaospy.Iid(chaospy.Uniform(), 2)
      >>> copula = chaospy.Gumbel(dist, theta=1.5)
  
  The resulting copula is then ready for use::
  
      >>> print(numpy.around(copula.sample(5), 4))
      [[0.6536 0.115  0.9503 0.4822 0.8725]
       [0.6286 0.0654 0.96   0.5073 0.9705]]
  """
  from .baseclass import Copula, Archimedean
  
  from .gumbel import Gumbel
  from .clayton import Clayton
  from .nataf import Nataf
  from .t_copula import TCopula
  