How to remove a variable from a folder having lots of pm file in it using a command

[Priti24]

I have a folder named like lib and this folder lib having multiple files and i have to remove one variable from all of files in folder lib

All files having lots of subroutines but also have a subroutine common. And i have to remove 1 argument of that subroutine from all files. Is this possible to delete this argument using a command or i'll have to do this manually

sub getSolrDocuments{
     my ($self,$records,$query_string) = @_;
     my $utils = Knimbus::Connectors::Utils->new;
     my $a = $utils->addFieldsToSolrDocuments($records, q{$a}, q{$b}, 
+q{$c}, q{$d}, $query_string);
     return $a;
 }

i have to remove 3rd argument($b) from addFieldsToSolrDocuments . value of $b is different in all files but position is same. Means i have to remove 3rd argument from all files<\p> is this possble using sed and grep command? Plz help me out......