code: def matrix_directed_unweighted(user):
      
      matrix = _interaction_matrix(user, interaction=None)
      for a in range(len(matrix)):
          for b in range(len(matrix)):
              if matrix[a][b] is not None and matrix[a][b] > 0:
                  matrix[a][b] = 1
  
      return matrix
docs: Returns a directed, unweighted matrix where an edge exists if there is at
      least one call or text.