Python implements two-dimensional array search (5-7)

#Def leftbottom(target, array) found from the lower left corner
 :
    line_num= len (array) #represents line
     col_num= len (array[ 0 ]) #represents column
 #first     search from
     the lower left corner col= 0
     line=line_num- 1
 while col<col_num and line>= 0 :
         if target<array [line][col]:    
            line-=1
elif target>array[line][col]:        
            col+= 1
 else :
             return True
     return False
 #Search from the upper right corner, the left ones are smaller than this element, and the lower ones are bigger than this element
 def righttop_find(arr,target): #Define
     line
 line_num= len (arr)
     #Define Column
 col_num= len (arr[ 0 ])
     #define the upper right corner element
 i= 0
 j=col_num- 1
 while i<line_num and j>= 0 :
         if target<arr[i][j]:                            
            j-=1
elif target>arr[i][j]:        
            i+=1
else:
            return True
    return False