code: def load(s):
      """Loads a boolean expression from a string.
  
      Examples
      ========
  
      >>> from sympy.logic.utilities.dimacs import load
      >>> load('1')
      cnf_1
      >>> load('1 2')
      cnf_1 | cnf_2
      >>> load('1 \\n 2')
      cnf_1 & cnf_2
      >>> load('1 2 \\n 3')
      cnf_3 & (cnf_1 | cnf_2)
      """
      clauses = []
  
      lines = s.split("\n")
  
      pComment = re.compile(r"c.*")
      pStats = re.compile(r"p\s*cnf\s*(\d*)\s*(\d*)")
  
      while len(lines) > 0:
          line = lines.pop(0)
  
          # Only deal with lines that aren't comments
          if not pComment.match(line):
              m = pStats.match(line)
  
              if not m:
                  nums = line.rstrip("\n").split(" ")
                  list = []
                  for lit in nums:
                      if lit != "":
                          if int(lit) == 0:
                              continue
                          num = abs(int(lit))
                          sign = True
                          if int(lit) < 0:
                              sign = False
  
                          if sign:
                              list.append(Symbol("cnf_%s" % num))
                          else:
                              list.append(~Symbol("cnf_%s" % num))
  
                  if len(list) > 0:
                      clauses.append(Or(*list))
  
      return And(*clauses)
  
imports: from sympy.core import Symbol
  from sympy.logic.boolalg import And, Or
  import re
label_desc: Use image node_id 1 for calling a global function with example usage: load(s) and returns: And