old_contents: """This module handles sequences.
  
  Copyright 2020 Michael Hayes, UCECE
  
  """
  
  from .expr import ExprList
  
  class Sequence(ExprList):
  
      def __init__(self, seq, n=None):
  
          super (Sequence, self).__init__(seq)
  
          # Save the indexes.  Ideally, should annotate which item
          # in sequence corresponds to n = 0.
          self.n = n
  
      def latex(self):
  
          items = []
          for v1, n1 in zip(self.n, self):
              s = v.latex()
              if n1 == 0:
                  s = r'\underline{%s}' % v1
              items.append(s)
  
          return '\left{%s\right\}' % ', '.join(items)
      
              
  
new_contents: """This module handles sequences.
  
  Copyright 2020 Michael Hayes, UCECE
  
  """
  
  from .expr import ExprList
  
  class Sequence(ExprList):
  
      def __init__(self, seq, n=None):
  
          super (Sequence, self).__init__(seq)
  
          # Save the indexes.  Ideally, should annotate which item
          # in sequence corresponds to n = 0.
          self.n = n
  
      def latex(self):
  
          items = []
          for v1, n1 in zip(self, self.n):
              try:
                  s = v1.latex()
              except:
                  s = str(v1)
              
              if n1 == 0:
                  s = r'\underline{%s}' % v1
              items.append(s)
  
          return r'\left\{%s\right\}' % ', '.join(items)
      
  
      def pretty(self):
  
          items = []
          for v1, n1 in zip(self, self.n):
              try:
                  s = v1.pretty()
              except:
                  s = str(v1)
              
              if n1 == 0:
                  s = '_%s_' % v1
              items.append(s)
  
          return r'{%s}' % ', '.join(items)
      
      
  
subject: Add pretty and latex for Sequence