text: 
  from ..data_class.data_manage import dataManager
  from .. import directories as direc
  import numpy as np
  import scipy.sparse as sp
  
  class tpfaScheme:
  
      def __init__(self, M: 'mesh object', data_name: 'nome do arquivo para ser gravado') -> None:
  
          self.mesh = M
          self.gravity = direc.data_loaded['gravity']
          self.n_nodes = len(M.data.elements_lv0[direc.entities_lv0[0]])
          self.n_faces = len(M.data.elements_lv0[direc.entities_lv0[1]])
          self.n_edges = len(M.data.elements_lv0[direc.entities_lv0[2]])
          self.n_volumes = len(M.data.elements_lv0[direc.entities_lv0[3]])
          self.data = dataManager(data_name)
          M.scheme = self
  
      def get_transmissibility_matrix_without_boundary_conditions(self) -> None:
          '''
          transmissibility matrix without boundary conditions
          '''
  
          M = self.mesh
          vols_viz_internal_faces = M.data.elements_lv0[direc.entities_lv0_0[2]]
          v0 = vols_viz_internal_faces
          internal_faces = M.data.elements_lv0[direc.entities_lv0_0[0]]
          transmissibility_faces = M.data.variables[M.data.variables_impress['transmissibility']]
          transmissibility_internal_faces = transmissibility_faces[internal_faces]
          t0 = transmissibility_internal_faces
  
          lines = np.array([v0[:, 0], v0[:, 1], v0[:, 0], v0[:, 1]]).flatten()
          cols = np.array([v0[:, 1], v0[:, 0], v0[:, 0], v0[:, 1]]).flatten()
          data = np.array([t0, t0, -t0, -t0]).flatten()
  
          T = sp.csc_matrix((data, (lines, cols)), shape=(self.n_volumes, self.n_volumes))
  
          self.data['Tini'] = T
  