'Change the type of orthogonal curvilinear system. It could be done
by tuple of transformation equations or by choosing one of pre-defined
coordinate system.
Parameters
:param curv_coord_type: str, tuple'

def _connect_to_standard_cartesian(self, curv_coord_type, inverse=True):

    if isinstance(curv_coord_type, string_types):
        self._set_transformation_equations_mapping(curv_coord_type)
        self._set_lame_coefficient_mapping(curv_coord_type)
        if inverse:
            self._set_inv_trans_equations(curv_coord_type)
    elif isinstance(curv_coord_type, (tuple, list, Tuple)):
        if ((len(curv_coord_type) == 3) and all((i.atoms(BaseScalar) for i in curv_coord_type))):
            self._transformation_eqs = curv_coord_type
            (self._h1, self._h2, self._h3) = self._calculate_lame_coefficients(curv_coord_type)
        elif (len(curv_coord_type) == 2):
            self._transformation_eqs = tuple([eq.subs({curv_coord_type[0][0]: self.x, curv_coord_type[0][1]: self.y, curv_coord_type[0][2]: self.z}) for eq in curv_coord_type[1]])
            (self._h1, self._h2, self._h3) = self._calculate_lame_coefficients(self._transformation_equations())
        else:
            raise ValueError('Wrong    set    of    parameter.')
        if inverse:
            self._inv_transformation_eqs = self._calculate_inv_transformation_equations(self._transformation_equations())
    else:
        raise ValueError('Wrong    set    of    parameter.')
    if (not self._check_orthogonality()):
        raise ValueError('The    transformation    equation    does    not    create    orthogonal    coordinate    system')
