parameters: (sa, sb)
return_statement: return ''.join(_iter())
docstring: returns the longest common substring from the beginning of sa and sb
docstring_summary: returns the longest common substring from the beginning of sa and sb
docstring_tokens: returns the longest common substring from the beginning of sa and sb
function: def common_from_start(sa, sb):
  	""" returns the longest common substring from the beginning of sa and sb """
  	def _iter():
  		for a, b in zip(sa, sb):
  			if a == b:
  				yield a
  			else:
  				return
  
  	return ''.join(_iter())
function_tokens: def common_from_start ( sa , sb ) : def _iter ( ) : for a , b in zip ( sa , sb ) : if a == b : yield a else : return return '' . join ( _iter ( ) )